OK 


/ 

/ 

/ 


SOLUBLE  GLASS 


AND 


ALL  ITS  APPLICATIONS. 


CONTAINING 


DIRECTIONS  FOR  RENDERING  WOOD  AND  TIMBER  FIRE 
AND  DRY  ROT  PROOF,  SILICIFYING  STONES,  MORTARS, 
CONCRETE  AND  HYDRAULIC  LIME,  WHITE  WASHES, 
PAINTS  AND  CEMENTS,  AND  HOVTTO  PROTECT 
WOODEN  SHINGLES,  PAVEMENTS,  RAIL- 
ROAD SLEEPERS,  &c..  &c. 


By  Dr.  LEWIS  FEUCHTWANGEE, 

CHEMIST  AND  MINERALOGIST. 


NEW  YOKK : 

PUBLISHED  BY  L.  &  J.  W.  FEUCHTWANGEE, 
No.  55  Cedar  Street. 
1873. 


INDEX. 


SOLUBLE  GLASS.     .       .       .       .  j 

The  Uses  of  Soluble  Glass  (Liquid  Silex). 
Silicate  of  Soda,  Silicate  of  Potash,  Silicate 
of  Soda  and  Potash  combined,         .       .  // 
ON  MORTARS  AND  CEMENTS,    .  21 
Common  Mo^da.r,       .       .       .       .  ,28 

Hydraulic  Ceinent^    ,       .       .       .       ,  2g 
The  Silicate  Hydraulic  Cement  in  the  pre- 
servation of  Wall-damp^         .        .        »  30 
Damp  Walls  a7td  Cellars,         .        .  • 
Mamfacture  of  Portland  Cement,      .  . 
Hydraulic  Mortar  from  American  Lime- 
stone,    .       .       .       .       ,       .  ,42 

German  Hydraulic  Cement,       ,       .  .46 
The  Uses  of  Hydratdic  Cement,         .       ,  50 
SILICA  TE  PAINTING,      ^       .       .  57 
Stereo-chrome  for  Easel  Painthig,      .        .  60 
SILICIFICATION  OF  WOOD,  .       .  62 
Wooden  Roof  Shingles,      .       .       .  ,66 
Decay  of  Wood  and  Processes  for  Preserv- 
ing it,  ,       .       .       .       .       .       .  ^7 

Timber  Rot  and  Seasoning,       ,       ,       »  70 


Index, 


Wooden  Roof  Shingles,     .       .       .  '74 
Street  Pavements,      .       ,       .       .  '75 
Various  Systems  Adapted  for  'Roadway 
Pavements,    .        .        .        .       .        •  7<^ 

The  Fiske  Co7icrete  Pavement^   ,       .       •  7/ 
The  Nicolsoii  Pavement,     .       .       .       •  7^ 
The  Stafford  Pavement,     .       .       .    -  .  7p 

CEMENTS: 
The  Most  Durable  Aquarium  Cement,       .  8i 
The  Soluble  Glass  as  Manure  for  Grape- 

viites,  82 
The  Soluble  Glass  as  a  Substitute  for  Glue,  8j 
Sohible  Glass  Application  for  vario7is  Ce- 
ments, • .       .       .       .       .       .       •  ^5 

An  Impermeable  Cement  Resisting  Steain,  86 
Hard  Ce7nent,  .       .       .       .       .  ,86 

Cement  for  Closing  Cracks  in  Stoves,         ,  8/ 
Ce7nent  for  a  Cistern,       ,       ,       ,       •  ^7 
A  Strong  Cement  for  Iron,       ,       ,  ,88 
Iron  Ceinent  for  Water  and  Gas  Pipes  and 
Castings,       .       .       .       .       ,.  ,88 

Colored  Cements,  ,  ,  .  .  ,88 
Coating  for  Outside  Walls,  ,  .  ,8^ 
Preservation  of  Sto7tes  from  Green  Coating,  8g 


PREFACE 


TO  THE  PRESENT  TREATISE. 


The  objects  of  this  condensed  volume  and  tlie 
causes  which  induced  the  author  for  its  issue, 
are  the  following : 

I.  The  two  last  Treatises  of  1870  and  1871, 
giving  a  detailed  description  of  the  manufacture 
and  uses  of  Soluble  Glass,  are  this  day  entirely 
exhausted,  not  having  been  stereotyped,  there 
is  not  one  copy  left. 

II.  The  programme  of  both  previous  editions, 
the  first  containing  additional  treatises  "  On  the 
functions  of  Carbonic  Acid  and  origin  of  Lime- 
stone," and  the  last  consisting  in  three  practical 
treatises  "On  Soluble  Glass,  on  Glass  Making, 
and  Guide  on  Soap  Making,''  were  deemed  as 
exceeding  the  main  object,  and  more  advisable 
of  touching  solely  on  the  application  of  Soluble 
Glass. 


iv  PREFACE. 

III.  The  great  improvement  lately  accom- 
plished by  the  author  in  producing  a  neutral 

silicate  which  could  answer  all  the  purposes  of 
painting,  pasting,  varnishing  and  soap  making, 

without  any  efflorescence  of  the  alkali,  is  the 

main  object  of  this  publication. 

lY.  The  price  of  the  former  editions  was,  by 

many  applicants,    considered   too  expensive, 

while  the  present  edition  can  be  supplied  at  a 

moderate  price. 

Respectfully  submitted  by  the  author, 

Lewis  Feuchtwanger. 


SOLUBLE  GLASS. 


It  is  also  called  liquid  quartz,  water  glass  or  alka- 
line silicate,  consisting  essentially  of  silex  and  either 
potash  or  soda,  or  both  together,  heated  to  fusion, 
and  it  is  therefore  a  silicate;  it  is  likewise  the  main 
comj)osition  of  all  kinds  of  glass ;  a  silicate  of  potash 
and  lime  is  the  Bohemian ;  a  silicate  of  soda  and 
lime  is  the  English  crown  or  spread  glass ;  if  there  is 
oxide  of  lead,  such  as  litharge,  or  red  lead,  is  added 
to  the  mixture  of  silex  and  alkalies  and  heated  to  con- 
tinued fusion,  we  obtain  thereby  a  flint  glass,  crystal 
glass  or  strass ;  the  latter  is  the  paste  used  in  mock  jew- 
elry. According  to  the  quantity  of  alkali  employed  in 
this  mixture  the  product  is  made  soluble  or  insoluble. 

THE  SOLUBLE  GLASS  has,  of  late,  become  para- 
mount in  the  arts,  as  many  trades  cannot  dispense  with 
it  in  their  pursuits,  and  more  so  since  the  great  confla- 
gration of  the  City  of  Chicago,  which  took  place  on  the 
9th  and  10th  of  October,  1871,  whereby  one-fifth  of  it 
was  laid  waste  and  destroyed ;  all  the  public  buildings, 
churches,  court-house,  the  principal  business  houses, 
and  many  wooden-roofed  houses  inhabited  by  poor 
people.  This  disaster  has  aroused  in  the  minds  of 
many  men,  and  journalists  in  particular,  the  question 
whether  or  not  such  a  catastrophe,  by  resorting  to 


4 


APPLICATION    OF  SOLUBLE  GLASS. 


more  precautions  in  the  construction  of  buildings  could 
not  be,  in  future,  either  entirely  avoided,  or  conflagra- 
tions of  any  magnitude  be  stayed  in  the  sudden  pro- 
gress of  the  fiery  element.  Well-informed  men  have 
so  expressed  their  belief  in  letters  to  the  Author,  that 
the  steeples  of  high  buildings  caught  from  the  sparks 
flying  in  all  directions  from  the  contagion,  and  could 
with  ease  have  been  saved  by  a  judicious  management. 
The  editor  of  the  Scientific  American  of  November 
11th  makes  the  following  pertinent  remarks  in  his 
leader  respecting  the  great  fire,  which  we  copy  here 
with  alacrity,  for  they  coincide  entirely  with  the 
Author's  ideas,  and  they  inspire  the  hope  that  all  the 
newspapers  in  United  States  may  take  due  notice  of 
such  valuable  hints  thrown  out,  and  copy  them  in 
their  own  local  papers,  so  that  all  readers  may  profit 
thereby,  and  follow  out  such  precautions  which  this 
journal  recommends,  and  whereby,  at  trifling  expense 
and  trouble,  millions  of  dollars  worth  of  property  can 
be  saved  to  owners  and  insurance  companies. 

He  speaks  of  suitable  building  material  in  the  fol- 
lowing article : 

"  Recent  events  have  turned  the  attention  of 
thoughtful  people  to  a  consideration  of  the  question  of 
building  material  for  large  towns.  It  no  longer  ap- 
pears proper  to  permit  indiscriminate  constructions, 
where  the  safety  of  a  whole  community  may  be  en- 
dangered. We  have,  in  large  cities,  superintendents 
of  buildings,  but  they  generally  confine  their  attention 
to  the  question  of  security  against  falling,  and  not  to 
the  character  of  the  building  material,  excepting  in  so 
far  as  wooden  structures  may  be  prohibited  in  certain 


APPLICATION  OF  SOLUBLE  GLASS. 


5 


districts.  There  would  now  appear  to  be  cogent 
reasons  why  commissioners  should  be  appointed  to 
secure  greater  precautions  than  the  mere  question  of 
wood  and  iron.  A  mixed  commission,  composed  of 
builders,  arcliitects,  underwriters,  firemen  and  scienti- 
fic experts,  could  be  appointed  to  study  the  whole 
subject  and  report  thereon  to  the  government.  The 
commission  could  very  properly  decide  upon  the  sur- 
vey of  streets,  and  the  width,  the  kind  of  pavement 
and  flagging  to  be  used.  They  could  lay  down  water 
pipes  and  establish  hydrants  at  suitable  distances, 
and  see  to  proper  arrangements  for  extinguishing  any 
fires  that  might  arise  ;  but  the  most  important  duty 
to  be  assigned  to  them  would  be  the  control  of  build- 
ing material  in  certain  sections  of  the  city. 

"  By  insisting  upon  the  construction  of  a  row  of 
buildings,  up  and  down  and  across  town,  as  nearly 
fireproof  as  it  is  possible  to  make  them,  a  wall,  imper- 
vious to  fire,  and  constituting  a  barrier  impassable  to 
any  ordinary  conflagration,  would  arrest  the  flames 
and  save  whole  sections  of  the  city.  A  street,  built  up 
entirely  of  fireproof  buildings,  would  be  a  novelty ;  * 
but  in  the  light  of  recent  events  it  would  appear  to 
offer  great  protection,  and  it  may  be  worth  while  to 
designate  what  streets  shall  be  of  this  character,  and 
then  insist  upon  a  compliance  with  the  prescribed 
style  of  building.  Having  adopted  some  such  plan  as 
this,  the  commission  would  have  to  study  tiie  kind  of 
building  material  best  adapted  to  city  structures, 
combining  security  and  durability  with  reasonable 
economy.  This  opens  up  the  whole  question  of  the 
compaft'ative  value,  for  building  purposes,  of  wood,  iron 


6 


APPLICATION^  OF  SOLUBLE  GLASS. 


and  stone.  They  tried  wood  in  Chicago,  without 
having  treated  any  of  the  material  with  the  numerous 
agents  that  have  been  recommended  to  render  it  in- 
combustible ;  and  the  sad  consequences  of  this  neglect 
ought  to  serve  as  a  warning  to  all  other  cities.  If  the 
wood  had  been  saturated  with  soluble  glass,  it  could 
not  have  been  set  on  fire.  Silicate  of  soda,  or  soluble 
glass,  can  be  obtained  in  sufficiently  large  quantities, 
and  at  such  reasonable  rates,  as  to  admit  of  the  pre- 
paration of  the  shingles,  clapboards,  and  all  exposed 
portions  of  frame  buildings.  Any  such  precaution  as 
this  has  the  double  advantage  of  protecting  against 
fire,  and  securing  against  decay  ;  and,  in  the  long  run, 
would  be  found  to  be  the  greatest  economy. 

"  If  people  will  insist  upon  constructing  frame  build- 
ings in  large  towns,  they  ought  to  be  compelled  to 
render  them  essentially  fireproof  by  the  above  chemi- 
cal mixture.  So  many  experiments  have  been  tried 
with  soluble  glass,  that  the  security  it  affords  against 
fire  and  decay  may  be  considered  as  fully  determined. 
Wood  thus  prepared  will  char  and  smolder,  but  will 
not  burst  into  flame ;  and  hence  there  could  be  no 
scattering  of  cinders  or  blowing  about  of  firebrands. 

"  In  reference  to  the  use  of  iron  for  houses,  the  facts 
that  it  is  employed  to  a  large  extent,  and  that  we  are 
constantly  acquiring  greater  skill  in  its  manipulation 
and  management,  are  sufficient  proof  of  its  practica- 
bility. In  Chicago,  however,  this  material  proved 
unavailing,  for  the  reason  that  the  wooden  structures 
made  a  fire  hotter  far  than  a  blast  furnace  constructed 
to  melt  pig  iron.  No  iron  could  stand  such  a  heat, 
and  it  melted  down  like  wax.    This  was  not  the  fault 


APPLICATION  OF  SOLUBLE  GLASS. 


7 


of  the  iron,  but  caused  by  tlie  neglect  to  prepare  the 
wood  against  such  an  emergency ;  and  no  one  will  be 
likely  to  condemn  iron  structures  on  account  of  their 
failure  in  Chicago. 

"  A  third  building  material  is  stone,  and  this  may  be 
divided  into  native  and  artificial.  There  are  a  good 
many  varieties  of  stone  suitable  for  building  purposes ; 
but  the  cost  of  quarrying,  transportation  and  working, 
is  so  great  in  this  country  as  almost  to  shut  this  mate- 
rial out  of  competition.  This  objection  does  not  apply 
to  artificial  stone.  The  lime  and  sand  required  to 
make  artificial  stone  can  be  found  nearly  everywhere. 
They  can  be  mixed  by  simple  machinery,  and  require 
no  labor  to  cut  them  into  shape  ;  but  the  plastic  mate- 
rial can  be  run  into  any  kind  of  a  mold,  where  it  dries 
in  a  few  hours,  and  one  layer  after  another  can  be 
carried  up  in  marvellously  short  time. 

"  For  rapidity  of  construction,  for  durability,  for 
security  against  fire,  for  warmth  and  ventilation,  for 
dryness  and  health,  for  economy,  for  architectural 
effects,  there  is  nothing  like  artificial  stone  ;  and  we 
look  upon  this  material  as  the  most  suitable  for  cities, 
and  as  probably  destined  to  supersede  all  other.  It 
only  needs  the  popular  dissemination  of  information 
on  the  subject  to  occasion  a  demand  for  artificial 
stone  ;  and  as  soon  as  such  a  demand  is  created,  tliis 
material  can  be  furnished  in  any  quantity  in  all  parts 
of  the  country  ;  and  we  shall  have  it  for  our  cellars 
and  our  ice  houses,  our  sewers,  cisterns,  wells,  water 
pipes,  paths,  roads,  schools,  churches,  dwelling  houses 
and  stores,  in  a  way  that  will  make  us  wonder  how  we 
ever  performed  the  slow  and  tedious  labor  of  hewing 


8 


APPLICATION  OF  SOLUBLE  GLASS. 


out  stones  or  laying  up  brick,  when  we  could  have 
formed  a  whole  house  at  one  casting — as  Krupp  pours 
the  melted  steel  into  moulds,  and  produces  a  cannon 
of  any  size." 

It  is  generally  known  that  the  Author  was  the  first 
to  introduce  the  soluble  glass  in  the  United  States, 
and  has  devoted  much  time  in  experimenting  with  it ; 
and  he  has  succeeded,  after  many  fruitless  trials,  to 
create  a  demand  in  many  branches  of  industry. 
From  the  extensive  list  of  patents  issued  in  Europe 
and  the  United  States,  he  has  collected  all  informa- 
tion, along  with  that  obtained  from  the  scientific  and 
practical  journals,  and  experimenters  will  find  in  this 
Treatise  the  various  uses  and  applications.  Kuhl- 
mann's  Pamphlet,  the  Mining  and  Engineering  Jour- 
nal, the  Transactions  of  the  American  Institute,  the 
Manufacturer  and  Builder,  Scientific  American,  the 
Annual  of  Scientific  Discovery,  have  all  furnished  ma- 
terial for  this  Treatise. 

Many  interesting  topics,  such  as  the  origin  of  salt- 
petre, the  nitrate  of  soda,  and  the  manufacture  of  blanc 
fix,  had  to  be  related,  and  will,  no  doubt,  interest  the 
general  reader. 

Particular  attention  has  been  bestowed  upon  the 
formation  of  hydraulic  cements  and.  artificial  stone, 
for  the  reason  that  more  inquiries  and  experiments 
are  performed  in  this  branch  than  in  any  other  of  do-, 
mestic  economy.  The  natural  stones,  such  as  the 
brown  stone,  sandstone,  limestone,  and  brick  building, 
will,  sooner  or  later,  after  an  exposure  to  the  atmos- 
pheric elements,  and  rain  and  frost,  become  decom- 
posed ;  cracks  and  fissures  Avill  then  produce  the  de- 


APPLICATION  OF  SOLUBLE  GLASS. 


9 


terioration,  ^vhile  coated  with  the  sohible  glass  and 
mixing  the  mortar  with  the  same  and  impregnating 
the  bricks,  much  is  gained  for  their  preservation. 

It  is  somewhat  remarkable,  that  long  before  this 
the  art  of  making  artificial  stone  has  not  been  brought 
to  perfection.  Yet,  if  we  may  judge  from  the  great 
and  increasing  variety  of  processes,  patented  and 
otherwise,  which  now  press  their  claims  upon  public 
notice,  the  time  is  ripe  for  the  introduction  of  any 
process  which  can  demonstrate  practically  its  capacity 
to  fulfill  the  requirements  of  the  case.  Every  oppor- 
tunity has  been  afforded  us  to  examine  and  test 
specimens  of  artificial  stone,  and  we  have  met  with 
many  kinds,  which  have  very  little  merit.  Some,  how- 
ever, are  really  good  stones,  and,  as  such,  must,  in  our 
opinion,  come  largely  into  use. 

The  silicification  of  railroad  sleepers,  wooden  rails 
and  blocks  for  pavement  is  in  importance  next  to  the 
preparation  of  artificial  stone.  The  comparison  of 
the  wooden  and  iron  rails  has  also  been  clearly  stated 
here,  and  the  future  will,  no  doubt,  bring  to  light 
many  facts  here  stated,  but  not  yet  put  to  practice. 
The  advantages  of  the  wooden  block  pavement  are 
numerous,  and  if  properly  laid,  will  withstand  long 
years  of  the  hardest  kind  of  travel  ;  and  there  are  but 
two  important  points  in  the  wooden  pavement  to  be 
observed,  which  are  a  firm  and  even  foundation,  and 
the  good  silicification  of  the  foundation  planks  and 
blocks. 

The  reason  why  the  Author  has  devoted  so  much 
space  upon  hydraulic  limes,  mortars,  paints,  white- 
washes, and  the   preparation  for  guarding  timber 


10 


APPLICATION  OF  SOLUBLE  GLASS. 


against  dry  rot  and  conflagration,  is  solely  to  prove 
and  make  it  plausible  that  the  application  of  soluble 
glass  possesses  great  advantages,  and  may,  with  very 
little  expense,  give  additional  safeguards. 

Siemens  recommends  for  the  production  of  a  white 
stouQ,  to  work  up  the  fine  silex  with  so  much  liquid 
soluble  glass  so  as  to  form  a  plastic  mass,  say  from 
3-4  parts  of  the  sand  may  be  required,  similar  to  pot- 
ter's clay,  and  adding,  at  the  same  time,  a  small 
quantity  of  chalk  and  fine  clay,  whereby  the  mass  be- 
comes more  uniform  and  compact.  Prepared  in  this 
manner,  objects  moulded  or  pressed  from  the  mass 
must  be  exposed  to  the  air  for  some  time. 

For  monuments,  millstones  and  other  building  ma- 
terial, he  uses  1  part  liquid  silica  to  2  parts  fine  sand 
and  12  parts  coarse  sand,  which  mass,  formed  into  the 
desired  sizes  or  objects,  after  being  dried  long  enough 
in  the  air,  are  left  in  a  heated  room  of  75°  for  several 
days,  and  even  to  the  boiling  point  of  water ;  they 
become  so  hard,  after  a  lapse  of  four  to  six  days,  that 
they  never  crack  or  fall  to  pieces.  It  is  also  recom- 
mended to  expose  the  mass  to  the  pressure  of  a  hy- 
draulic press  before  exposing  to  the  air.  For  obtain- 
ing a  cement — roofing  and  wall  body — it  is  advisable 
to  add  the  chloride  of  calcium  to  the  mass,  and  thereby 
the  excess  of  alkali  is  absorbed. 

The  mass  so  formed  may  be  steeped  in  a  solution 
of  chloride  of  calcium,  or  chloride  of  iron,  before  ex- 
posing to  the  atmosphere.  In  all  these  cases  the  silica 
ought  to  be  employed  very  concentrated,  even  in  jelly 
form. 

The  uses  of  the  soluble  glass  are  here  condensed  in 


APPLICATION  OF  SOLUBLE  GLASS. 


11 


a  short  sketch,  intended  as  a  circular  to  those  desirous 
of  obtaining  some  information  : 

"  THE  USES  OF  ^SOLUBLE  GLASS  (LIQUID  SILEX)  SILICATE 
OE  SODA,  SILICATE  OF  POTASH,  SILICATE  OF  SODA 
AND  POTASH  (COMBINED). 

"  Liquid  silica  is  now  employed  in  the  arts  for  many 
useful  purposes,  and  particularly  for  preser-v;jing  stone 
buildings  from  decomposition  ;  for  preparing  an  arti- 
ficial stone,  and  thereby  reducing  the  price  of  build- 
ing, and  making  a  composition  more  ornamental.  Its 
introduction  for  architecture  is  but  of  recent  da-te,  and 
the  true  and  proper  method  of  application  not  yet  on 
an  infallible  base  ;  but  the  subject  is  of  so  vast  impor- 
tance, that  experiments  are  continually  going  on  for 
making  a  perfect  stone  from  its  original  ingredients. 

"  The  cause  of  gradual  decomposition  of  building 
stone  is  attributed  to  the  expansion  and  contraction 
of  water  absorbed,  as  well  as  to  the  chemical  action 
of  carbonic  acid  of  the  atmosphere,  which  abstracts 
portions  of  the  gases  from  the  silicates,  and  liberating 
thereby  silica.  Many  places  in  Europe,  churches  and 
other  public  buildings,  have  been  refinished  by  the 
silicate,  such  as  the  Louvre  and  Notre  Dame  Cathe- 
dral in  Paris,  the  Houses  of  Parliament  in  London, 
and  in  other  cities.  Still,  its  general  application  has 
met  with  many  failures.  It  was  found  that  rain  coun- 
teracted the  effect  before  the  alkali  has  had  time  to 
take  up  a  sufficient  quantity  of  carbonic  acid  from  the 

*  lu  the  year  1882  Dr.  F.  prep  ired  a  qu'mlity  of  soluble  y:las3  for  the 
U.  S.  Governmeut  to  prei<e;  ve  the  caunon  etin«  and  bocub-Bhella  from 
ru8t  or  oxydiition  at  tho  Navy  Yaid  ia  Biooklyn,  to  the  fullent  satisfaotiou 
of  the  late  ConimodOi'e  Perry. 


12 


APPLICATION    OP  SOLUBLE  GLASS. 


atmosphere  and  to  liberate  the  insoluble  silicate  ;  the 
coating  will  produce  cracks,  and  a  gradual  disintegra- 
tion of  the  surface  or  compound  is  caused  thereby. 
Numerous  remedies  were  suggested  to  counteract  this 
evil — the  ghloride  of  calcium,  oxychloride  of  magne- 
sium, the  bittern  of  salines,  and  hydrofluoric  acid. 
At  present  a  concrete  stone  Of  considerable  hardness 
and  durability  is  now  prepared  by  means  of  greater 
pressure  and  proper  manipulation,  the  main  object 
being  to  neutralize  and  extract  the  alkali,  and  to  form 
a  solid  chemical  compound  by  a  second  application  of 
of  a  weak  wash  of  chloride  of  calcium  or  magnesium. 
The  object  is  now  fully  achieved. 

"  Another  important  application  of  the  soluble  glass 
is  to  render  wood  non-inflammable,  and  to  stop  any 
communication  of  the  fire,  and  at  the  same  time 
proof  against  water  and  damp.  The  wood,  timber  or 
other  substances,  after  being  boiled  for  several  hours 
in  the  soluble  glass,  then  exposed  in  tanks,  contain- 
ing solution  of  lime  water  and  solutions  of  chloride 
of  calcium,  are  hereb}^  petrified. 

"Railroad  sleepers,  cross-ties,  house,  ship  and 
bridge  timber,  will  also  be  silicified  by  this  process. 
Telegraph  poles  become  more  durable  and  better  non- 
conductors of  electricity.  The  lining  of  barrels  for 
oil  and  other  liquids,  the  coating  of  tanks,  tubs  and 
cisterns,  flour  barrels,  to  prevent  the  flour  getting 
must}^,  is  very  easy  and  effectually  done  by  the  projDer 
and  judicious  use  of  liquid  silica. 

"  Soluble  glass  may  be  mixed  with  paper  pulp,'  or 
che;ip  vegetable  and  animal  fibre,  and  serve  for  th( 
manufacture  _of  a  variety  of  useful  articles,  such  as 


APPLICATION   OF  SOLUBLE  GLASS. 


13 


boxes,  trunks,  soles  for  boots  and  shoes,  patterns, 
moulds  and  handles.  Invaluable  and  of  the  highest 
usefulness,  the  soluble  glass  can  be  employed  in  fire-proof 
paints,  cements,  varnishes,  etc.^  for  ivhich  purposes  the 
daily  demands  are  sufficient  proofs. 

"  The  dentists  make  use  of  the  sihca  for  mending 
their  plaster  moulds,  or  in  case  of  an  accident  to  the 
east  of  a  set  of  teeth.  Valuable  documents  are  made 
fireproof,  and  parchment  board,  slates  and  marbles 
are  cemented  together,  and  cracks  and  crevices 
filled  up. 

"  The  wool  growers  apply  the  silicate  of  soda  and 
potash  to  the  greatest  advantage  for  cleansing  or  de- 
greasing  the  fleece  wool  and  make  it  soft. 

"  The  waste  of  wool  or  cotton  used  in  the  locomo- 
tive engines  to  sustain  the  lubricating  materials,  may 
be  cleaned  and  made  new  by  the  aid  of  soluble  glass. 

"  A  hard  and  ornamental  cement,  which  can  be 
moulded  like  plaster  of  Paris,  is  obtained  from  the 
mixture  of  silicate  of  soda  and  ground  dolomite  or 
magnesian  limestone,  which  may  be  used  both  natural 
and  calcined  in  equal  quantities,  and  before  the  mass 
is  dry,  the  bittern,  (chloride  of  magnesium)  from  the 
salines  is  added,  which  will  harden  it  at  once.  A 
good  cellar  and  roofing  cement  is  made  by  adding  to 
this  mass  three  parts  of  white  sand. 

"  The  silicate  is  also  used  for  penetrating  fire-brick 
and  clay,  in  order  to  make  them  more  fire-proof,  and 
also  used  for  cementing  the  walls  ;  for  producing  a 
durable  putty  in  iron  castings,  such  as  furnaces,  heat- 
ers, stoves,  etc.,  and  also  for  mending  air  holes. 
Boiler  makers  can  produce  a  very  durable  lining  by 


14 


APPLICATION   OF  SOLUBLE  GLASS. 


making  a  cement  of  silicate  witli  asbestos  and  man- 
ganese finely  ground  ;  it  renders  boilers  and  other 
metallic  vessels  perfectly  fire-proof,  and  the  best  fire 
and  anti-rust  paint  for  iron,  steel  and  brass.  There 
are  a  great  many  more  useful  applications  in  which 
the  silicate  may  be  used." 

The  alkaline  silicates,  as  have  been  here  described, 
have  a  bright  future  for  their  application  :  the  genius 
of  the  nineteenth  century  cannot  fail  to  accomplish 
the  perfecting  the  work  begun  fifty  years  ago,  and  to 
this  moment  still  liable  to  faults.  Ere  long  we  will 
be  enabled  to  produce  an  artificial  stone  which  shall 
excel  nature  ;  we  will  be  able  to  produce  a  perfect 
silification  of  wood  and  other  organic  matter ;  we 
will  challenge  the  atmosphere  and  other  chemical 
productions  to  do  their  best  for  forming  a  decomposi- 
tion of  these  materials  obtained  by  the  new  acquired 
skill  to  resist  their  action.  The  labors  of  Fuchs,  Lie- 
big,  Kuhlmann,  Yicat,  Fremy,  Guerin  and  Eansome 
have  fairly  begun  their  work,  and  in  ten  years  more 
the  ship  builder,  carpenter,  mason,  painter,  the  rail- 
road contractor,  and  the  mechanic  in  general,  will 
consider  this  valuable  substance  indispensable. 

The  author  has,  many  j^ears  ago,  in  the  course  of 
his  experiments,  succeeded  in  preparing  an  artificial 
stone  in  the  following  manner  : — Fluorspar,  finely 
ground,  is  mixed  with  the  powdered  soluble  glass,  2 
parts  of  the  first  to  1  part  of  the  latter,  the  mixture 
made  into  a  thin  paste  by  the  concentrated  liquid 
soluble  glass,  and  then  as  much  finely  powdered  shell 
limestone,  or  magnesian  limestone  added,  until  the 


APPLICATION   OF  SOLUBLE  GLASS.  15 


mass  becomes  thick  enough  to  form  into  moulds  or 
blocks,  whichever  may  be  desired ;  after  an  exposure 
of  three  to  four  days  to  the  atmosphere,  are  treated 
by  a  weak  solution  of  chloride  of  calcium,  (2  pounds 
dry  chloride  to  the  gallon  of  hot  water)  this  liquid 
will  soon  be  absorbed  by  the  stone ;  it  is  then  exposed 
again  to  the  atmosphere  for  a  week ;  a  dilute  hydro- 
fluoric acid  is  then  applied  with  a  sponge,  and  again 
exposed  to  the  atmosphere ;  after  a  lapse  of  a  week 
the  stone  is  as  hard  as  a  natural  stone,  and  not  liable 
to  crack  or  to  disintegrate. 

This  composition  is  much  easier  prepared,  and  in- 
stead of  common  lime  chalk  may  be  substituted,  and 
the  result  is  still  more  favorable.  Instead  of  the  entire 
quantity  of  lime,  coarse  sand  may  be  partially  added, 
and,  after  the  stones  are  moulded,  are  exposed  to 
hydraulic  pressure,  and  then  exposed  to  the  air,  pre- 
vious to  which  the  chloride  of  calcium  has  to  be  thrown 
over  it.  The  price  of  hydro-fluoric  acid,  as  is  used  for 
this  purpose,  costs  about  25  cents  per  pound,  and  this 
sufiices  for  ten  square  feet. 

Furthermore,  it  may  be  remarked  that  exposing  the 
stone  so  prepared  may  be  subjected  to  a  high  tem- 
perature or  not ;  it  may  be  left  to  the  operator  to 
decide  whether  it  will  improve  the  stone  by  *tiiis  mani- 
pulation. 

For  the  sandstone  imitation,  when  1  part  liquid 
soluble  glass  is  to  be  mixed  with  2  parts  powdered 
soluble  glass,  and  15  parts  of  sand  is  added,  it  is 
necessary  to  expose  the  mass  to  great  pressure,  but 
requires  not  the  addition  of  calcium,  while  exposuf  e  to 
great  heat  is  indispensable. 


16 


APPLICATION  OF  SOLUBLE  GLASS. 


An  artificial  stone  may  be  also  obtained  by  the  use 
of  the  alkaline  silicates  with  common  chalk,  which,  by 
mixing  even  cold  with  the  liquid  silica,  is  at  once  con- 
verted into  silicate  of  lime  and  carbonate  of  soda,  or 
potash ;  this  composition,  when  exposed  to  the  air, 
becomes  in  a  few  days  hard  enough,  so  as  to  resemble 
a  hydraulic  lime,  to  adhere,  when  wetted  again,  like  a 
cement,  which  may  be  used  for  restoring  cracks  and 
crevices  in  marble  works  and  monuments. 

The  silicification  of  chalk  has  led  to  numerous  ex- 
periments, and  resulted  in  the  production  of  artificial 
stone,  in  the  formation  of  hydraulic  lime,  hydraulic 
mortar,  and  the  various  cements.  The  first  successful 
result  of  the  treatment  of  chalk  with  the  silicate  solu- 
tion has  shown  that  the  hardening  of  the  chalk 
extended  to  the  depth  of  four  inches,  which  not  alone 
was  produced  from  the  decomposition  of  the  silicate 
by  the  carbonate  of  lime  (chalk),  but  also  by  the  car- 
bonic acid  of  the  atmosphere.  If  two  balls  of  chalk 
of  equal  size  and  quality  are  silicified  at  the  same  time, 
and  one  of  them  is  exposed  to  the  atmosphere,  the 
other  kept  under  a  bell  glass,  where  the  carbonic  acid 
of  the  atmosphere  is  withdrawn,  the  first  will  acquire 
more  hardness  than  the  other,  which  proves  that  the 
silicification  has  assumed  a  hydrate  of  silico — carbonate 
of  lime — which  loses  by  degrees  its  water  of  crystalliza- 
tion, and  forming  a  precipitate  of  silica,  contributing 
mainly  to  the  hardening  of  the  stone. 

A  hydraulic  lime  may  be  obtained  by  the  mixture  of 
a  fat  or  rich  limestone  combined  with  soluble  glass  in 
a  dry  state,  say  10  parts  silicate  to  100  parts  of  air 
lime,  both  fine  powder,  which  proves  plainly  the  theory 


It 

APPLICATION    OF  SOLUBLE  GLASS.  17 

of  the  part  which  the  silicates  play  in  the  production 
of  the  native  limestone,  the  artificial'  hydraulic  lime, 
mortar,  cements,  and  the  application  of  all  silicates  for 
the  purposes  of  building,  production  of  artificial  stones, 
and  the  conversion  of  organic  into  inorganic  materials, 
as  we  shall  show  hereafter. 

Wood,  paper,  linen  and  straw,  when  covered  with 
several  coats  of  soluble  glass,  are  no  longer  inflam- 
mable, but  simply  char  when  exposed  to  fire.  It  also 
prevents  the  decay  and  rotting  of  wood,  and  keeps 
out  worms.  Beer  barrels,  butter  firkins  and  milk  tubs 
can  be  easily  kept  clean  when  painted  with  soluble 
glass,  and  the  same  is  true  of  vessels  designed  to  hold 
sugars,  syrups,  wines,  petroleum,  etc.  The  most  im- 
portant use  of  soluble  glass  is  its  application  to  sur- 
faces of  stone  and  mortar.  For  this  purpose  it.  is 
necessary  to  impregnate  the  surface  with  a  solution 
composed  of  one  part  33  degrees  and  three  parts  rain 
water. 

Mortar  and  porous  limestones  react  upon  the  solu- 
ble glass,  producing  carbonate  of  lime,  hydrate  of 
lime,  and,  ultimately,  silicate  of  lime,  which  thus  pre- 
sents an  impervious,  vitreous  surface,  capable  of 
resisting  the  action  of  moisture  and  the  atmosphere, 
and  is  in  a  proper  state  for  fresco-painting,  in  mineral 
colors.  Organic  colors  are  apt  to  be  destroyed  by 
the  alkali  of  the  soluble  glass,  and  hence,  for  fresco- 
painting,  mineral  paints  are  alone  available.  A 
second  coating  of  paint,  rubbed  up  with  soluble  glass, 
is  iisually  sufficieni  for  all  practical  purposes,  and  a 
wall  thus  treated  can  be  washed  with  soap  and  Avater, 
and  kept  thoroughly  clean.    A  plain,  white  color  is 


18  APrLTCA-TTON  OF  SOLUBLE  GLASS. 

obtained  by  mixing  clialk  with  soluble  glass.  Zihv, 
white,  and  silicate  of  soda  set  so  rapidly,  that  it  is 
necessary  to  add  $  to  ^  its  weight  of  precipitated 
sulphate  of  baryta  before  applying  the  color.  Baryta, 
white  and  soluble  glass  also  afford  a  good,  fast  color. 
Fluor-spar,  with  pulverized  glass  and  soluble  glass, 
also  gives  an  exceedingly  solid  mass.  The  pigments 
that  have  been  found  by  experience  to  serve  the  best 
purpose  are  chromate  of  zinc,  sulphate  of  cadmium, 
blue  and  green  ultramarine,  Schweinfurth  green,  ox- 
ide of  chromium,  cinnabar,  etc.  Prussian  blue  and 
colors  prepared  from  it,  and  chromate  of  lead,  will 
not  answer,  as  they  are  destroyed  by  the  alkali,  the 
same  as  organic  colors.  It  is  well  known  that  the 
fresco-painting  in  the  capitol  at  Washington,  in  the 
new  museums  in  Berlin  and  Munich,  are  done  with 
water-glass,  and  that  the  success  in  their  use  is  com- 
plete. 

Soluble  glass,  with  or  without  colors,  adheres 
closely  to  such  metals  as  iron,  zinc  and  brass,  and 
protects  them  from  the  influences  of  the  air  and 
water.  It  has  been  found  that  when  stoves  are 
painted  with  a  mixture  of  soluble  glass  and  black  ox- 
ide of  manganese,  a  species  of  flux  is  produced  by  , 
the  heat  which  does  not  scale  off,  but  thoroughly  pro- 
tects the  iron  from  any  corroding  action.  Plate  glass, 
when  coated  with  the  soluble  silicate,  becomes  opaque, 
and  when  baryta  is  mixed  with  the  liquid  quartz,  it 
assumes  a  fine,  white  appearance.  If  the  glass  be 
heated  it  becomes  enameled,  lilfe  porcelain ;  and 
fixed  colors,  such  as  ultramarine  and  oxide  of  chro- 
nium,  open  up  an  extensive  application  for  soluble 


APPLICATION  OF  SOLUBLE  GLASS.  19 

glass  for  transparencies,  cliurch  windows,  etc.  The 
manufacture  of  artificial  building  stone  by  means  of 
soluble  glass  has  been  conducted  in  Germany  and 
England  on  an  extensive  scale.  In  Vienna  barracks  of 
an  enormous  size  have  been  constructed  of  such  arti- 
ficial stone  ;  and  the  tower  of  the  Cathedral  in  that 
city  was  put  into  thorough  repair  in  the  only  way 
that  was  possible,  considering  the  great  height  of  the 
tower  and  the  extent  to  which  it  had  fallen  to  decay. 

When  ground  chalk  or  marble  is  stirred  into  a 
paste  with  soluble  glass,  the  mass  becomes  so  hard 
that  it  can  be  employed  for  building  purposes,  or  for 
the  restoration  of  decayed  stone  structures. 

Marble  and  dolomite  immersed  in  a  solution  of 
soluble  glass,  and  the  operation  repeated  a  number 
of  times,  take  up  an  appreciable  quantity  of  silica, 
and  become  so  hard  that  they  are  capable  of  taking  a 
fine  polish.  Attempts  to  employ  such  stones  for 
lithography  have  been  made,  but  not  altogether  with 
success.    Artificial  stone  can  be  prepared  as  follows  : 

Well  washed  and  gently  heated  sand  is  stirred  into 
a  warm  solution  of  soluble  glass  until  a  proper  con- 
sistence has  been  reached  for  pouring  it  into  a  mould. 
After  it  has  set  it  is  removed  from  the  frame,  which 
ought  to  have  been  previously  oiled,  and  is  left  to  dry 
in  an  airy  place.  To  avoid  too  great  a  consumption 
of  water  glass,  a  stone  or  brick  can  be  put  in  the  cen- 
tre of  the  mould.  It  is  also  possible  to  stir  in  peb- 
bles and  to  use  earthly  colors  in  imitation  of  marble 
and  conglomerate.  Such  artificial  material  becomes 
very  hard,  and  is  adapted  to  pavements,  hearths  and 
•building  purposes. 


20  APPLICATION  OF  SOLUBLE  GLASS. 

Soluble  glass  can  be  used  in  the  manufacture  of 
paper  hangings,  for  printing  on  paper  and  woven 
fabrics,  for  attaching  gold  and  silver  powder  to  any 
kind  of  object. 

Hydraulic  lime  can  be  prepared  by  mixing  in  fine 
powder  10  to  12  parts  by  weight  of  dry  soluble  glass 
and  100  parts  of  lime — this  affords  a  ready  way  of 
preparing  a  hydraulic  cement  from  ordinary  lime, 
which  is  always  available. 

One  of  the  earliest  and  best  known  uses  of  soluble 
glass  is  a  cement  for  glass,  porcelain  and  metals. 
It  is  put  up  in  small  packages  for  this  purpose,  and 
sold  on  the  corners  of  streets  under  various  names. 
Pieces  of  glass  or  porcelain  cemented  in  this  way  will 
break  more  readily  in  places  which  were  whole,  than 
where  they  were  repaired.  The  solution  ought  to  be 
quite  concentrated  when  employed  for  this  purpose. 
The  fragments  to  be  repaired  must  be  heated  to  the 
boiling  point  of  water,  and  both  surfaces  be  then 
moistened  with  the  cement  and  pressed  closely  to- 
gether, and  held  in  position  by  a  strong  cord,  and 
left  to  dry  in  a  warm  place.  By  mixing  sulphate  of 
magnesia  or  calcined  magnesia  and  soluble  glass,  a 
cement  can  be  formed  that  can  be  cast  into  moulds, 
and  very  generally  be  substituted  for  meerschaum. 

Wood  and  timber  and  other  porous  substances, 
after  being  boiled  for  several  hours  in  soluble  glass, 
then  exposed  in  tanks  containing  lime  water  or  chlo- 
ride of  calcium,  and  left  to  dry,  become  higlily  vitri- 
fied and  incombustible.  Railroad  ties,  ships'  timber, 
house  and  bridge  beams,  have  been  treated  in  this 
manner  with  entire  success. 


ON  MORTAR  AND  CEMENTS. 


21 


The  silicate  is  also  used  for  penetrating  fire  brick 
arid  clay,  and  for  cementing  the  walls  of  furnaces. 

When  stirred  up  with  chloride  of  calcium  and  used 
for  luting  down  the  covers  of  crucibles,  it  answers  an 
excellent  purpose. 


ON  MOKTAR  AND  CEMENTS. 

"  The  earliest  architectural  constructions  to  fasten 
together  the  bricks  or  stones  of  which  buildings  are 
made  were  of  various  kinds  ;  the  most  common  is 
called  mortar.  It  is  obtained  by  first  calcining  crude 
hmestone  in  a  kiln,  and  converting  it  into  quicklime, 
by  depriving  it  of  its  carbonic  acid.  After  calcining, 
the  resulting  qiiickiime  is  of  a  whitish  or  grayish  pow- 
dery and  cracked  substance,  which,  on  the  application 
of  water,  absorbs  a  certain  quantity  with  the  evolution 
of  much  heat,  and  crumbles  into  a  fine  powder.  This 
powder  further  moistened,  made  into  a  thin  paste 
with  water,  and  mixed  with  two  or  three  times  its  own 
weight  of  sharp  sand,  is  called  mortar.  Slaked  lime, 
or  hydrate  of  lime,  as  moistened  quicklime  is  called, 
absorbs  carbonic  acid  from  the  air,  and  in  time  mor- 
tar is  reconverted  into  limestone  ;  but  the  operation 
goes  on  under  peculiar  conditions,  and  the  result  is 
also  peculiar  ;  for  a  film  of  silicate  of  lime  is  formed 
round  each  grain  of  sand,  and  thus  the  whole  mass 
and  the  stones,  between  which  it  is  placed,  become  in 
time  more  compact  than  the  particles  of  limestone. 

"  As,  however,  there  are  different  kinds  of  limestone, 
more  or  less  impure,  the  result  will  be  limes  of  very 


22 


ON  MORTAR  AND  CEMENTS. 


different  qualities  and  properties.  These  require 
special  treatment  to  obtain  from  them  the  best  results. 
The  purest  carbonate  of  lime,  such  as  marble,  or 
chalk,  make  what  is  called  a  rich  lime,  setting  firmly 
only  in  dry  air,  while  the  very  impure  carbonates,  in 
which  clay  is  largely  mixed  with  the  hmestone,  result 
in  the  production  of  hydraulic  limes,  which  set  more 
or  less  rapidly  in  moist  air  or  even  under  water. 
Some  of  the  impure  limestones  are  used  in  the  manu- 
facture of  cements  by  the  admixture  of  definite  pro- 
portions of  foreign  ingredients.  Sometimes,  by  the 
admixture  of  certain  substances  (as  puzzuolana)  with 
the  rich  limes,  instead  of  sand,  hydraulic  limes  are 
produced.  There  are  few  subjects  connected  with  the 
apphcation  of  geology  that  are  more  important,  than 
the  determination  of  the  material  that  should  be  used 
and  the  treatment  adopted  in  various  countries  in  the 
manufacture  of  cements,  mortars  and  stuccoes. 

"  Commencing  with  nearly  pure  carbonates  of  lime, 
it  is  not  difiicult  to  trace  the  changes  that  take  place 
in  their  conversion  into  cements;  a  layer  of  such 
mortar,  not  too  thick,  placed  between  bricks  or  stone, 
which  are  themselves  absorbent,  and  kept  in  dry  air. 
dries  gradually  and  holds  together  such  substances 
with  extraordinary  tenacity.  But  this  is  a  work  of 
years,  and  sometimes  even  centuries  must  run  out 
before  the  extreme  of  hardness  is  attained  !  It  is  not 
unusual  to  find  imperfectly  hardened  mortars  in  very 
old  constructions.  The  mortar  that  fastened  together 
the  bricks  in  the  old  Eoman  walls  is  now  almost 
everywhere  so  far  hardened  that  a  fracture  takes  place 
in  the  brick  rather  than  in  the  cement. 


ON  MORTAR  AND  CEMENTS. 


23 


"  Limestone  is  widely  distributed,  and  almost  every 
variety,  however  impure,  can  be  burnt  into  lime.  In 
the  manufacture  of  good  common  mortar  to  set  in 
the  air,  pure  limestones  and  those  of  fair  ordinary 
quality  are  available  ;  but  in  using  them,  attention 
must  be  given  their  composition  and  even  texture  ; 
thus,  the  hardest  limestones  and  marbles  make  the 
fattest  lime,  but  each  variety  yields  a  lime  of  difierent 
quality,  distinct  in  color,  in  weight,  in  the  greediness 
with  which  it  absorbs  water,  and  in  its  ultimate  hard- 
ness. The  method  of  calcination  also  varies,  but  the 
general  result  is  that,  after  burning  the  limestone,  the 
resulting  quicklime  is  lighter  than  the  original  stone, 
and  differs  from  it  essentially. 

The  word  hydraulic,  as  applied  to  lime,  means  only 
that  it  possesses  the  property  of  setting,  or  becoming 
solid,  in  moist  air  or  under  water. 

"  Eich  limes  are  obtained  from  the  purest  and 
hardest  limestones.  When  slaked,  they  increase  to 
double  their  volume ;  if  employed  alone,  they  remain 
unaltered  even  for  years,  and  they  are  soluble  in  pure 
water.  Limestones  which  contain  from  1  to  6  per  cent, 
of  foreign  substances,  such  as  silica,  alumina,  magne- 
sia, etc.,  yield  rich  limes ;  but  such  as  contain  from  15 
to  30  per  cent.,  are  poor  limes ;  they  increase  in  bulk, 
but  little  on  slaking,  do  not  set  under  water,  and  are 
soluble,  like  the  rich  limes,  except  that  they  leave  a 
residuum.  The  fossiliferous  limestones  make  bad 
mortar,  as  the  slaking  is  irregular ;  limestones  contain- 
ing much  silica  swell  in  setting,  and  may  dislocate  the 
masonry  executed  with  them.  Where  alumina  is  in 
excess,  the  lime  is  apt  to  shrink  and  crack.  Where 


24 


ON  MORTAR  AND  CEMENTS. 


carbonate  of  magnesia  is  combined  wifcli  carbonate  of 
lime,  as  in  the  magnesian  limestones,  the  original  bulk 
is  retained.  For  ordinary  purposes,  moderately  pure 
limestones,  with  a  mixture  of  foreign  substances,  is  a 
moderately  pure  limestone.  Hydraulic  limes  are  of 
great  value  in  construction,  and  are  extremely  inter- 
esting, and  are  either  obtained  naturally  from  the 
burning  of  certain  varieties  of  calcareous  rock,  or  are 
manufactured  artificially  by  mixing  limestones  with 
the  requisite  foreign  ingredients ;  such  are  the  Roman 
cement,  Portland  cement,  Parker's  and  Rosendale 
cements.  The  Portland  cement  is  largely  manufac- 
tured at  the  mouth  of  the  Thames  from  a  mixed  river 
mud,  while  Roman  cement  is  formed  from  the  nodules 
found  in  the  cliffs  near  Harv/ich,  all  owing  their  quality 
to  argillaceous  admixture.  Limestone,  containing 
from  15  to  25  per  cent,  of  a  silicate  of  alumina,  will 
burn  into  a  good  hydraulic  lime.  It  is  also  quite, 
certain  that  the  oxide  of  iron  and  carbonate  of  masf- 
nesia  exercise  a  great  influence  in  rendering  limes  mora 
hydraulic.  All  materials  intended  for  the  manufac-. 
ture  of  cements  require  to  be  burnt  carefulty,  and 
ground  down  to  a  fine  powder,  and  the  best  cement  is 
the  lightest.  When  these  cements  are  intended  for 
the  production  of  an  artificial  stone,  from  ten  to  twelve 
times  the  weight  of  broken  pebbles  are  added,  and 
form  also  an  excellent  concrete.  A  stone  made  from 
these  cements  just  described,  Avill  bear  a  strain  varj-ing 
from  20-60  pounds  to  the  square  inch. 

"The  plaster  cement  is  obtained  from  the  gypsum, 
or  sulphate  of  lime,  abundant  in  England,  France,  and 
the  United  States ;  is  treate  i  lilie  common  limestone 


ON  MORTATl  AND  CEMENTS. 


25 


for  a  cement.  The  calcining  of  gypsum  does  not  in- 
volve its  decomposition,  but  the  water  of  solidification 
being  driven  off  by  the  calcination,  leaves  only  a  soft 
white  powder  called  plaster  of  Paris  ;  when  this  is 
again  united  with  water,  the  latter  is  absorbed,  and 
the  mass  becomes  first,  plastic,  and  then  solid;  but  it 
cannot  be  brought  back  to  its  original  condition  as  a 
crystalline  mineral,  but  it  is  converted  into  various 
substances  used  as  a  cement,  such  as  Keenes  cement, 
if  alum  is  added  to  the  fine  powdered  plaster ;  parian 
cement,  if  borax  is  used ;  Martin's  cement,  if  pearl 
ashes  are  employed.  Stucco  is  a  very  useful  material 
for  ornaments  for  in  and  out-door  work,  is  nothing  else 
but  a  plaster  of  Paris,  finely  ground,  and  a  weak  glue 
added  before  mixing  it  with  water. 

"  One  of  the  richest  kinds  of  hydraulic  lime  may  be 
obtained  from  volcanic  minerals  mixed  with  limes ; 
such  material  is  the  Puzzuolana,  found  near  Naples, 
as  well  as  other  substances  found  in  large  quantities 
in  the  neighborhood  of  extinct  volcanic  districts,  as  in 
France  and  on  the  Rhine  ;  and  which,  according  to  its 
chemical  analysis,  consists  of  44  per  cent,  of  silica,  15 
per  cent,  alumina,  87  per  cent,  lime,  4  per  cent,  mag- 
nesia, and  12  per  cent,  oxide  of  iron ;  combined  with 
lime  instead  of  sand,  have  the  property  of  rendering 
even  the  richest  limes  hydraulic,  and  fit  for  use  for 
every  description  of  works  executed  in  the  sea  or 
in  the  fresh  water;  they  have  been  used  from  thn'e 
immemorial  v^^ith  great  success,  arid  may  be  mixed 
either  with  fat  or  hydraulic  limes  and  silicate  of  soda 
to  form  a  plastic  mass,  and  assist  in  the  setting  of  the 
lime. 


26 


ON  MORTAR  AND  CEMENTS. 


"  In  many  cases  the  chemical  composition  of  an 
argillaceous  limestone  is  not  only  the  condition  which 
determines  the  quality  of  the  cement  ;  the  reaction  of 
the  lime  upon  the  clay  must  take  place  at  the  highest 
temperature.  Indeed,  this  excessive  heat  produces 
the  hydraulic  elements  of  the  cement  in  the  basic 
conditions  which  the  setting  in  the  water  requires, 
and  which,  by  melting  the  aluminate  of  lime,  gives  it 
all  its  activit3\ 

*'  The  Roman  or  hydraulic  cement  mostly  contains, 
also,  magnesia  and  iron ;  whether  of  any  essential 
benefit  or  not,  has  not  been  fairly  tested.  It  is  cer- 
tain that  neither  of  these  substances  exercise  a  per- 
nicious influence,  for  the  reason  that  dolomite,  a 
magnesian  limestone  found  in  great  abundance  in 
this  country,  offers  a  fine  mineral  when  calcined  with 
any  marls,  so  abundant  along  our  coast.  In  produces 
an  excellent  hydraulic  cement. 

"  The  analysis  of  the  hydraulic  lime  from  Rondout, 
on  the  North  River,  gives  in  one  hundred  parts : 


Carbonic  a:' id  35 

Magnesia  12 

■ '      •  10 


Lime  26 

Silica  15 

Iron 


"  Sand  or  quartz,  wdiicli  by  itself  is  unfit  for  a  mor- 
tar, when  calcined  wdth  lime,  becomes  very  suitable 
for  a  hydraulic  cement  or  artificial  stone,  for  it  forms 
a  silicate  of  lime.  More  than  thirty  years  ago,  I  en- 
tertained the  idea  of  preserving  timber  by  the  infiltra- 
tion of  silicate  of  lime  into  the  cells  of  planks, 
timber,  and  through  the  double  chemical  affinity  of 
silicate  of  soda  and  sulphate  of  lime.    The  experi- 


ON  MORTAR  AND  CEMENTS. 


27 


ments  I  made  then,  in  the  Brooklyn  Navy  Yard,  with 
pier  piles  and  wooden  vats,  were  very  satisfactory. 

"  For  water-proofing  cellars  and  buildings,  not 
alone  the  best  hj^draulic,  but  other  cements  have  of 
late  years  been  introduced  in  this  city  ;  for  instance, 
the  asphalt  cement,  which  is  very  extensively  em- 
ployed in  the  foundation  of  buildings.  Having  made, 
myself,  many  experiments,  for  a  number  of  years 
past,  in  order  to  introduce  the  silica  cement,  or  the 
soluble  glass  in  combination  with  alkaline  earths  as  a 
base,  and  met  with  varied  success,  I  beg  to  offer  here 
a  sample  of  a  cement  which  consists  of  silicate  of 
lime  combined  with  manganese  and  fluorspar,  or 
fluoride  of  calcium,  which  becomes  very  hard,  and 
which,  I  think,  will,  after  some  improvement  in  the 
preparation,  be  found  highly  useful  in  keeping  dry 
walls  and  cellars.  I  have  mixed  equal  quantities  of 
manganese,  limestone,  fluorspar,  and  dry  soluble 
glass,  and  make  the  whole  mass  plastic  by  the  liquid 
soluble  glass,  and  apply  it  while  soft ;  after  the  lapse 
of  a  few  hours  it  becomes  very  hard. 

"  Among  the  great  variety  of  cements  in  which 
silica  is  the  active  principle,  the  two  following  are 
very  useful  : 

"  1.  A  mortar,  to  be  made  as  hard  as  any  cement, 
and  which  does  not  crack  in  setting,  and  even  of  great 
usefulness  as  hydraulic  cement  under  water,  is  ob- 
tained by  mixing  finely  slaked  lime  with  fine  sand 
(the  angular  grains  are  always  preferable  to  the 
round  grains  for  producing  a  good  mortar,) — by  mix- 
ing the  sand  thus  prepared  with  finely  powdered 
quicklime,  and  stir  the  mixture  thoroughly.  During 


28 


ON  MORTAR  AND  CEMENTS. 


tli6  process  tlie  mass  heats,  and  may  then  be  em- 
ployed as  a  mortar,  to  which  has  to  be  added  to  one- 
eighth  of  the  mass  the  hquid  sihcate  of  soda. 

"  One  part  of  good  slaked  Hme  was  used  with  three 
parts  of  sand,  and  to  this  was  added  three-fourths  of 
its  weight  of  finely  powdered  quicklime  ;  the  mortar 
containing  one-eighth  of  the  liquid  silicate  of  soda 
was  then  used  as  a  foundation  wall,  and  in  four  days 
had  become  so  hard  that  a  piece  of  sharp  iron  would 
not  attack  it ;  and  in  two  months  afterwards  it  had 
become  as  hard  as  the  stones  of  the  wall. 

"  2.  A  thin  coating  of  slaked  lime  made  into  paste 
with  water  or  whitewash  is  put  at  once  on  the  stone, 
and  before  becoming  quite  dry  apply  the  silicate  so- 
lution over  the  paste,  by  which  means  the  mass  be- 
comes completely  insoluble ;  a  petrification  takes 
place  if  applied  to  vegetable  substances,  decomposi- 
tion is  prevented,  porous  building  stone  and  brick  are 
protected  against  air  and  damp. 

"  Common  Mortar. 

"  Limestone,  an  impure  carbonate  of  lime,  when 
exposed  to  a  red  heat,  loses  carbonic  acid  gas,  and 
the  oxide  of  calcium  or  lime  remains.  This  process 
of  burning  lime,  as  it  is  called,  is  accelerated  by  the 
presence  of  moisture  in  the  stone,  or  by  the  introduc- 
tion of  a  small  quantity  of  steam  into  the  lime  kiln. 
The  hydrate  of  lime  reacts  with  considerable  power 
on  siliceous  comj^ounds,  bat  the  action  only  takes 
place  at  the  surfaces,  and  unless  the  lime  is  used  in 
very  thin  layers,  between  smooth  stones,  it  still  re- 


ON  MORTAR  AND  CEMENTS. 


29 


tains,  in  the  centre  of  the  layer,  its  own  soft  and 
friable  condition. 

"  In  order  to  make  the  hydrate  of  lime  effective  as 
a  cement,  it  is  mixed  with  sand,  one  of  the  most 
abundant  of  natural  compounds,  now  regarded  as 
consisting  of  two  atoms  of  oxygen  and  one  of  silicon. 
Equal  parts  of  fine  and  coarse  sand  are  said  to  be 
better  than  either  quality  used  separately  with  lime. 
Mortar  designed  for  exterior  or  surface  work  is  gene- 
rally made  with  fine  sand.  When  lime  is  compara- 
tively free  from  impurities,  and  crumbles  to  a  fine 
powder  on  being  slaked,  it  is  called  fat  lime,  and  will 
require  about  six  times  its  own  weight  of  sand,  or,  if 
estimated  by  bulk,  one  cubic  foot  of  semi-fluid  lime 
and  w^ater,  called  the  milk  of  lime,  will  require  about 
three  or  four  cubic  feet  of  sand.  This  mortar  is  very 
effective  as  a  cement  when  well  dried  or  set,  but  if  it 
is  placed  in  water,  the  lime  is  gradually  dissolved  and 
the  mass  is  disintegrated. 

"  Hydraulic  Cement. 

"  For  all  permanent  structures  under  water  it  is, 
therefore,  essential  to  use  a  material  called  hydraulic 
cement,  which  is  a  mixture  of  lime  with  other  oxides 
possessing  the  valuable  quality  of  hardening  until 
it  has  the  solidity  and  permanency  of  the  masses  of 
rock  bound  together  by  it.  The  varieties  of  limestone 
from  which  hydraulic  cement  is  made,  when  burned, 
yield  a  lime  that  is  very  slowlv  slaked.  All  that  is 
required  is  to  add  water  until  it  attains  the  consist- 
ency of  dough  ;  it  will  then  harden  and  become  con- 
crete.   These  hydraulic  limes  may  be  made  artificially 


30 


ON  MORTAR  AND  CEMENTS. 


by  mixing  with  impure  slaked  lime  a  quantity  of 
burnt  clay  in  the  proper  proportions.  The  celebrated 
Roman  cement  is  a  porous  volcanic  rock  found  at 
Pazzuoli,  near  Naples,  and  called  there  puzzuolana. 
It  consists  of  silicate  of  alumina,  soda  and  lime. 
This  substance  is  pulverized  and  mixed  with  common 
Hme." 

The  S1LICA.TE  Hydraulic  Cement  in  the  Prevention 
OF  Wall-Damp. 

In  laying  the  foundation  of  any  building,  the  mat- 
ter of  particular  consideration  should  be  the  thorough 
drainage  of  the  site,  and  next  to  that  complete  pre- 
vention of  wall-damp,  that  is,  the  rising  of  moisture 
by  capillary  attraction  or  otherwise,  in  the  heart  of 
the  brick  or  stone  work,  the  particulars  of  which  have 
been  lately  described  in  the  Manufacturer  and  Dtdlder^s 
Journal,  to  which  the  author  had  added  the  silicifica- 
tion  of  the  bricks  and  plaster.  It  states  that  wher- 
ever brickwork  comes  in  contact  with  the  earth,  or 
even  with  adjacent  walls  which  may  happen  to  be 
damp,  there  the  infection  is  certain  to  take,  and  there 
is  no  easy  cure  for  it,  if  once  it  makes  an  entrance. 

The  readiest  remedy  in  all  cases  is  a  layer  of  fine 
concrete,  which  may  bo  thinly  coated  on  the  top  with 
asphaltum  laid  on  hot.  This  done  all  around  the  top 
of  the  walls,  external  and  internal,  the  piers  and  every 
piece  of  brickwork,  that  in  any  manner  has  connec- 
tion with  the  ground,  then  the  bricks,  which  ought  to 
be  specially  pi'epared  before  calcination  with  a  sili- 
cate solution,  should  be  heated  over  charcoal  furnaces 
and  dipped  in  the  asphaltum  before  being  laid.    It  is 


ON  MORTAR  AND  CEMENTS. 


31 


evident  that  a  preventive  course  could  thus  be  formed 
above  ground  at  a  trifling  expense,  wholly  impervious 
to  wall-damp,  at  the  same  time  giving  a  base  to  the 
superstructure  of  a  quality  very  far  superior  to  any 
now  in  use.  Coating  the  outside  face  of  the  wall  with 
water-proof  silicated  cement,  as  has  been  before 
noticed,  is  the  only  safeguard  against  capillary  attrac- 
tion from  below,  and  excluding  the  external  air  which 
might  let  the  artificial  heat  of  the  rooms  to  attract  the 
enemy  of  wall-damp.  It  is  known  that  common  brick 
will  absorb  one-fifth  of  its  weight  of  water,  and  where 
the  storm  drives  the  rain  continually  against  the  face 
of  a  wall  for  a  sufficient  time  to  permit  the  interior 
heat  to  attract  it,  the  inside  of  the  wall  must,  of  ne- 
cessit}^,  be  damp,  and  the  papering  become  mouldy, 
as  well  as  the  ceiling,  will  next  be  rotton.  This  cause 
of  wall-damp  is  one  that  cannot  be  too  carefully 
guarded  against,  as  it  is  one  to  which  may  be  referred 
the  early  decay  of  many  residences,  as  well  as  the  in- 
ception of  these  pulmonary  symptoms  which  so  surely 
steal  away  the  health  and  ultimately  the  life  of  many 
a  victim. 

The  mortar  to  be  used  in  the  foundation  and  the 
wall  ought  to  be  very  well  prepared,  so  as  to  possess 
all  the  h3^draulic  properties  and  silicification,  and 
caution  should  be  taken  in  not  using  sea  sand,  which 
will  certainly  create  the  damp  by  absorbing  all  the 
water  in  the  atmosphere,  this  being  the  chemical  effect 
of  its  saline  property. 

Tbe  surface  of  the  walls  of  the" rooms  must  be  well 
attended  to ;  the  plaster  of  Paris,  which  is  generally 
employed,  ought  to  be  properly  silicified,  so  as  to 


32 


ox  MOHTAPt  AND  CEMENTS. 


prevent  tlie  absoi^ption  of  the  natural  damp  of  tlie 
atmosphere  created  in  uninhabited  and  unheated 
rooms. 

It  is  preferable  to  paint  rooms  than  to  paper  them, 
for  the  white  lead  and  linseed  oil,  with  some  man- 
ganese to  facilitate  the  drying,  becomes  hard  after  a 
short  time,  and  assists  the  fresh  plaster  wall  in  pre- 
venting the  admission  of  the  moisture,  as  the  fourth 
coating  of  white  lead  is  applied  with  equal  portions  of 
oil  and  spirits  of  turpentine,  which  has  the  property 
of  being  very  volatile,  will  evaporate  entirely,  leaving 
the  surface  of  the  paint  of  a  very  compact  and  hard 
■nature,  and  rendering  the  plaster  incapable  of  absorp- 
tion. 

Damp  Walls  and  Cellars. 

The  application  of  silicates  for  preventing  the  pene- 
tration of  rain  or  moisture  in  houses,  whereby  the 
wails  are  absorbing  the  same,  and  render  the  paper- 
•  hangings  or  delicate  paint  unfit,  so  as  to  destroy  their 
appearance,  has  been  amply  and  satisfactorily  proved. 
The  silicates  of  soda  and  potash,  or  either  of  them,  are 
mixed  with  pure  white  lead  or  zinc,  and  applied  soon 
after  upon  the  walls,  which  will  dry  immediately. 

The  presence  of  damp  in  walls  arises  from  three 
causes :  either  from  the  porous  condition  of  the  mate- 
rials of  which  they  are  built,  allowing  the  penetration 
of  damp  from  without ;  from  the  existence  of  salts  in 
the  mortar,  bricks  or  stone,  which  absorb  and  give  out 
moisture,  according'  to  the  changes  of  tlie  weather,  or 
from  damp  foundations.  The  first  only  can  be  reme- 
died by  the  application  of  external  coatings,  the  second 


ON  MORTAR  AND  CEMENTS. 


33 


by  battening  the  walls,  and  tlie  last  by  removing  the 
adjacent  earth  from  the  foundations. 

As  has  already  been  stated,  a  single  application  of 
a  paint  formed  with  lead  or  zinc  has  proved  very  suc- 
cessfal.  The  second  application  is  the  silicate  solution 
with  china  clay,  or  pure  alumina,  which'  has  the  advan- 
tage of  not  drying  so  quick  as  that  with  lead  or  zinc. 
In  all  cases  the  paints  must  be  put  on  uniformly,  so 
that  the  whole  wall  surface  should  be  completely 
covered  with  the  solid  coat ;  and  in  order  to  effect  this, 
a  rough  stucco  surface,  from  two  to  three  coats,  may 
be  required.  It  is  found  also  useful  to  apply  the 
second  coat  thinner  than  the  first. 

The  mixture  of  liquid  silicate  of  soda  with  clay  and 
that  of  whiting,  or  washed  carbonate  of  lime,  may 
probably  be  the  most  reliable  for  keeping  out  damp 
from  walls  as  well  as  cellars. 

On  applying  the  lead  or  zinc  as  the  first  coat,  either 
of  them  or  both,  it  may  be  done  in  the  following 
manner : 

Mix  them  with  a  little  water  and  lay  them  on  the 
stone ;  they  will  dry  very  soon  ;  apply  then  the  silicate 
solution  by  means  of  a  syringe.  If  the  application  is 
to  be  made  on  stone  which  shows  some  decay,  it  is 
necessary  to  remove  first  the  same ;  apply  then  the 
aluminous  silicate  of  soda  (by  an  equal  mixture  of 
liquid  silicate  with  fine  white  clay),  and  then  apply 
the  carbonate  lime  and  silicate  wash  with  an  ordinary 
paint  brush,  stippling  it  so  as  to  give  it  the  appearance 
of  the  granulated  surface  of  the  stone.  When  dry,  it 
will  adhere  sufficiently  to  allow  of  other  washes  of 
silicates  being  brushed  on  it. 


ON  MORTAR  AND  CEMENTS. 


The  conditions  necessary  for  success  are  : 

1.  The  wall  should  be  coated  with  a  porous  mate- 
rial, such  as  lime  or  Portland  cement. 

2.  The  coating  must  be  perfect.  A  wall  which  has 
been  once  painted  is  altogether  unfit  for  any  applica- 
tion of  siliceous  washes,  for  the  reason  that  it  is  not 
absorbent  enough. 

The  best  ground  for  any  siliceous  work  is  lime  and 
sand.  In  new  buildings  it  would  be  better  to  use  lime 
and  sand  at  once,  and  then  to  cover  it  with  lime  and 
silicate  of  alumina  and  soda.  The  precipitated  sul- 
phate of  baryta  may  safely  be  applied  in  thie  silicate 
of  soda  for  all  the  above  purposes,  and  it  will  produce 
a  good  coating  and  a  fine  paint. 

Manufacture  of  Portland  Cement. 

Portland  cement  was  introduced  to  public  notice 
under  a  patent  by  an  Englishman,  nearly  fifty  years 
ago,  and  a  partial  monopoly  in  its  production  has  been 
kept  up,  inasmuch  as  inexhaustible  beds  of  the  raw 
material  from  which  it  is  made,  and  an  abundant  sup- 
ply of  fuel  necessary  for  their  economical  manufacture, 
is  at  hand.  It  is  strange  that  under  these  conditions 
French  engineers  should  have  obtained  the  start  of 
their  professional  confreres,  and  that  they  should  have 
been  the  first  to  demonstrate  by  experiments,  and 
subsequently  by  the  erection  of  magnificent  harbor 
works  on  their  seaboard,  the  valuable  properties  of  this 
excellent  constructive  material.  We  may  date  the  ex- 
tensive employment  of  Portland  cement  in  England 
from  the  commencement  of  the  metropolitan  main- 
drainage  works.    During  the  last  fifteen  3'ears  the 


ON  MOETAR  AND  CEMENTS. 


35 


matiufacture  of  Portland  cement  has  gone  on  steadily 
increasing,  until  at  the  present  day  we  find  that  little 
short  of  400,000  tons  per  annum  are  made  in  the 
county  of  Kent — the  centre  of  cement  manufacture — 
irrespective  of  the  productions  of  many  minor  factories 
in  difierent  parts  of  the  country. 

The  chemistry  of  the  setting  of  Portland  cement  is 
by  no  means  so  well  understood  as  it  ought  to  be. 
There  is  no  doubt,  however,  that,  like  the  hydrauhc 
lime  and  natural  cements,  it  is,  chemically  speaking, 
a  double  silicate  of  lime  and  alumina ;  silicic  acid  is 
generated  by  the  hydration  of  the  cement,  and  forms 
insoluble  salts  with  the  lime  and  alumina  bases.  It  is 
a  curious  fact  that  Portland  cement  hardens  more 
rapidly  when  salt  water  is  employed.  According  to 
Schweitzer,  1,000  grains  of  sea-water  in  the  English 
Channel  contains  27,060  grains  of  chloride  of  sodium  ; 
soluble  silica  has  a  known  preference  for  alkaline 
bases,  and  it  is  not  improbable,  when  the  cement  is 
hydrated  with  sea- water,  that  the  chloride  of  sodium 
is  decomposed,  the  silicic  acid  of  the  cement  combin- 
ing with  the  sodium  and  oxygen  of  the  water,  and 
forming  thereby  a  silicate  of  soda,  or  a  species  of  crude 
glass. 

Portland  cement  is  of  two  classes,  which,  for  the  sake 
of  distinction,  may  be  termed  "  Engineers'  "  cement 
and  "Plasterers'"  cement.  The  former  is  the  more 
costly ;  it  is  usually  described  by  manufacturers  as 
"  best  heavy  tested  ;"  it  weighs  from  112  pounds  to 
120  pounds  to  the  bushel,  is  slow  setting,  and  of  great 
strength  ;  the  latter  is  a  light  cement,  qnick  setting, 
and  of  inferior  strength  Avhen  compared  with  the  other. 


36 


GN  MORTAR  AND  CEMENTS. 


It  must  be  understood  that  our  remarks  apply  exclu- 
sively to  "  Engineers'  "  cement. 

Portland  cement  is  made  from  clialk  and  alluvial 
clay  ;  the  factories  on  the  banks  of  the  Thames  use 
white  chalk,  those  on  the  Medway  gray  chalk  ;  the 
latter  is  probably  preferable,  inasmuch  as  it  contains 
large  quantities  of  silicious  matter.  Mr.  Read,  in  his 
treatise  on  "  Portland  Cement,"  says  that "  the  pre- 
sent and  safest  proportions,  provided  both  chalk  and 
clay  are  selected  free  from  sand,  are  four  parts  of 
chalk  from  the  Medway,  (gray,)  or  three  parts  of 
Thames,  (white,  with  one  of  clay  by  measure."  These 
materials  are  placed  in  mills  of  simple  construction, 
each  having  a  circular  pan,  6  feet  in  diameter  and  2 
feet  deep,  in  which  two  "  edge  runners,"  4  feet  6 
inches  in  diameter,  are  kept  continually  going ;  a  con- 
stant stream  of  water  flows  into  the  pan,  and  as  the 
"  edge  runners  "  revolve,  the  chalk  and  clay  are  thor- 
oughly ground,  and,  being  thus  converted  into  a  fluid 
state,  they  filter,  through  a  band  of  fine  brass  wire 
gauze  fixed  to  the  side  of  the  pan,  and  flow  through 
wooden  "  launders  "  into  tanks  or  settling  reservoirs. 
One  wash -mill  v.'ill  feed  four  tanks,  each  of  which"  is 
about  100  feet  long,  40  feet  broad,  and  4  feet  deep. 
When  one  of  these  has  been  filled  in  the  manner  just 
described,  the  same  process  is  applied  to  the  others 
in  succession.  About  three  weeks  after  the  tanks  are 
filled,  the  whole  of  the  materials  will  be  precipitated, 
the  clear  water  being  drained  off  in  the  meantime 
through  a  small  weir  in  the  brick  side  of  the  tank  ; 
the  residuum  is  a  plastic  mixture  of  the  consistenc\ 
of  "  putty,"  and  not  much  unlike  it  in  color.  The 


ON  MOETAR  AND  CEMENTS. 


37 


next  process  is  to  convey  this  precipitate  from  the 
tank  'to  the  "  drying  floors,"  over  which  it  is  spread 
in  a  layer  about  6  inches  thick ;  each  floor  is  40  feet 
by  30  feet ;  it  consists  of  an  outer  skin  of  boiler 
plates,  sufficiently  hot  to  effect  the  rapid  desiccation 
of  the  water  from  the  superincumbent  layer,  a  pro- 
cess generally  accomplished  in  about  twelve  hours. 
The  materials  having  thus  been  thoroughly  dried,  are 
ready  for  conveyance  to  the  kilns.  The  "charge" 
consists  of  alternate  layers  of  coke  and  raw  mate- 
rials, the  burning  generally  occupying  thirty-six 
hours.  When  the  contents  of  the  kiln  become  suffi- 
ciently cool,  the  "  clinkers,"  or  cement  stones — for  the 
mixture  has  now  assumed  that  form — are  drawn  and 
removed  to  a  floor  where  the  larger  pieces  are  bro- 
ken, and  the  whole  of  the  burnt  materials  are  then 
conveyed  to  the  hoppers  of  the  grinding  mills,  where, 
passing  under  rapidly-revolving  horizontal  burr- 
stones,  they  are  ground  into  an  almost  impalpable 
powder.  The  cement  issues  from  the  mill  at  a  tem- 
perature of  about  160  degrees,  and  the  now  manu- 
factured material  is  wheeled  away,  and  placed  in  a 
layer  from  2  feet  to  3  feet  thick  over  the  floor  of  a 
cool  shed  ;  it  is  subsequently  packed  in  casks  or  sacks 
for  conveyance  from  the  works.  The  essential  condi- 
tions for  the  manufacture  of  good  Portland  cement 
are :  1.  The  chalk  and  clay  should  be  thoroughly 
mixed  in  the  wash-mills,  and  the  fluid  materials  de- 
livered by  "  launders  "  over  tlie  enfire  area  of  the 
settling  tanks.  2.  The  contents  of  the  kilns  ought  to 
be  burnt  equally  throughout.  3.  The  burnt  mate- 
rials should  be  ground  very  fine.    4.  After  coming 


38 


ON  MORTAR  AND  CEMENTS. 


from  the  mill  tlie  cement  should  be  spread  over  the 
floor  of  a  shed,  and  allowed  to  remain  there  for  at 
least  a  fortnight  previously  to  being  packed  in  casks 
or  sacks. 

The  strength  of  Portland  cement  increases  as  its 
specific  gravity  increases  ;  the  tensile  tests  are  usu- 
ally made  with  briquettes,  the  standard  size  for  the 
neck  being  1\  in.  by  IJ  in.  ;  and  it  must  be  under- 
stood that  all  experiments  referred  to  have  reference 
to  the  weight  necessary  to  sever  2|  square  inches  of 
neat  cement. 

It  appears  from  Mr.  Grant's  valuable  paper,  read 
before  the  Institution  of  Civil  Engineers  in  December, 
1865,  that  Portlond  cement  gains  from  20  to  30  per 
cent,  in  strength  by  setting  under  water  ;  it  is  usual, 
therefore,  to  place  the  best  briquettes  in  water,  after 
gaging,  and  allow  them  to  remain  there  until  they  are 
to  be  tested.  The  following  table  has  been  compiled 
from  a  recent  series  of  experiments^  ;  it  shows  the 
average  tensile  strength  of  Portland  cement  as  com- 
pared with  the  natural  cements  ;  the  test  blocks  were 
of  standard  size  of  2|  square-  inches,  and  placed  in 
water,  as  before  described  : 


Weight  per 
bushel. 

1 

Breaking  weight 
two  days  old. 

Breaking  w6-ght 
lour  days  old. 

-  §2 
o  o 

%  ^ 

it 
a 

lbs. 

lbs. 

lbs. 

lbs. 

119 

598 

914 

1.024 

76 

200 

240 

280 

09 

280 

313 

313 

Cement  do  Zumaya,  (Spanish. ) 

84 

306 

403 

ON  MORTAR  AND  CEMENTS. 


39 


Portland  cement  now  forms  an  important  item  in 
the  list  of  our  manufactures  ;  but  even  now  its  valua- 
ble properties  are  not  ^s  fully  appreciated  as  they 
deserve  to  be.  It  should  present  a  fine  and  homoge- 
neous powder  ;  it  should  set  firmly  and  quickly,  when 
used  in  works  exposed  to  the  surf,  filling  up  joints  in 
water  works,  etc.,  otherwise  too  rapid  setting  is  not 
desirable.  It  should  neither  contract  nor  expand  ;  it 
ought  to  assume  a  uniform,  bright,  gray-stone  color, 
free  from  brown  spots  ;  it  should  possess  great  ce- 
menting properties,  adhere  strongly  to  the  stone,  and 
bear  a  high  addition  of  sand.  Finally,  it  ought  to  be 
free  from  adulterations,  while  the  ton  should  have  the 
generally  adopted  weight  of  200  kilogrammes.  It  is 
to  be  recommended,  under  all  circumstances,  and 
even  if  the  cement  has  been  procured  from  well- 
known  manufacturers,  to  weigh  it  on  delivery,  and  to 
keep  an  accurate  account  of  it.  It  is  very  often  the 
case  that  the  weight  is  considerably  below  200  kilo- 
grammes, due  either  to  the  frequent  use  of  the  same 
barrel,  which  almost  inevitably  .gets  smaller,  or  to 
bad  packing,  which  produces  incompactness ;  or  to 
unpacking  it  in  smaller  barrels,  which  is  often  done 
by  second  or  third  hand  dealers. 

A  difference  of  ten  or  twenty  kilogrammes  per  ton, 
which  often  occurs  away  from  the  centres  of  trade, 
ought  certainly  to  be  taken  into  consideration,  if  oc- 
curring in  larger  quantities. 

In  order  to  examine  cements  for  their  fineness  and 
uninformity  of  mixture,  it  is  only  necessary  to  pass 
samples  or  different  barrels  through  sieves  of  twenty 
meshes  per  centimetre. 


40 


ON  MORTAR  AND  CEMENTS. 


There  should,  properly  speaking,  reraain  nothing  on 
the  sieve,  and  under  all  circumstances,  preference 
must  V)e  given  to  the  cement  which  most  nearly  fulfills 
these  conditions ;  for  the  finer  and  more  uniformly 
the  cement  is  diyided,  the  more  promptly  and  simul- 
taneously will  the  chemical  reactions  take  place,  the 
more  perfect  its  combining  and  cementing  properties, 
and  the  less  fear  is  to  be  entertained  about  a  dura- 
bility of  the  mass  after  it  has  once  properly  set.  The 
most  common  adulterations  are  inferior  or  spoiled 
cement,  slags,  ashes,  clay  and  sand.  They  are  most 
easily  discovered  by  constant  shaking  of  a  sample 
with  an  abundant  amount  of  water,  after  which  it  is 
allowed  to  settle  in  a  high,  narrow  vessel.  The 
cement  to  be  examined  is  to  be  put  in  the  glass  filled 
two-thirds  full  of  water,  after  which  it  must  be  shaken 
at  once,  or  the  cement  will  cake  together  and  stick  to 
the  vessel.  Ashes  and  clay  deposit  on  top,  on  ac- 
count of  their  smaller  specific  gravity,  and  the  water 
in  this  case  genera,lly  looks  turbid.  The  upper  por- 
tion of  the  sediment  generally  fails  then  to  harden  at 
*  all,  but  exhibits  a  distinctly  different  color  from  the 
rest  of  the  mass.  A  close  examination  of  it  will  then 
usually  disclose  the  nature  of  the  adulteration. 

When  made  into  paste,  with  sufiicient  water  to  pro- 
duce a  mortar  which  slides  smoothly  from  the  trowel, 
pure  cement  should  not  set  in  less  than  twenty  or 
thirty  minutes. 

Yet  the  view  that  the  most  quickly-setting  cement 
is  the  best,  is  found  to  be  quite  generally  disseminated. 
We  read,  for  instance,  in  a  book  on  this  subject  of  re- 
cent date  :  "  Excellent  cements,  such  as  the  Portland 


ON  MORTAR  AND  CEMENTS. 


41 


cement,  Eoman  cement,  and  others,  if  immersed  in 
water,  harden  in  a  few  minutes,  wliile  inferior  cements 
only  attain  after  a  few  hours  such  a  degree  of  hard- 
ness that  they  will  not  take  an  imjDression  b}  the 
fingers." 

This  view  is  not  quite  correct,  for  it  can  be  proven 
that  rapidly-hardening  cements  will,  under  otherwise 
equal  circumstances,  never  attain  such  a  degree  of 
solidity  and  strength  as  slowly-setting  ones.  They 
will,  therefore,  not  bare  the  same  amount  of  sand. 

Rapidly-setting  cements  ought,  therefore,  to  be 
avoided  when  possible,  and  only  used  in  filling  up 
cracks  in  water  works,  or  for  similar  purposes  :  firstly, 
because  they  fail  to  attain  the  same  degree  of  solidity 
and  power  of  resistance  as  the  slowly-setting  ones; 
secondly,  because  they  can  only  be  worked  with  diffi- 
culty in  small  quantities,  and  only  giving  the  best  re- 
sult of  which  they  are  capable,  when  the  mason  is 
exceedingly  prompt  and  skillful ;  thirdly,  because*  they 
accomplish  much  less  than  they  really  should  by 
being  worked  in  a  careless  manner,  besides  causing 
considerable  dela}^ 

For,  if  the  hardening  process  has  once  begun  in  the 
mortar -box,  the  most  assiduous  working  up  of  the  so- 
lidifying mass  will  not  (especially  if  more  water  is 
added)  entirely  remedy  the  evil. 

By  employing  slow-binding  cements,  these  draw- 
backs are  in  a  great  measure  avoided.  Portland  ce- 
ment, which,  if  mixed  with  the  necessary  amount  of 
water,  say  from  thirty  to  forty  per  cent,  in  weight,  and 
if  not  setting  in  less  than  twenty  minutes,  will 
scarcely  increase  in  temperature  ;  quickly -hardening 


42 


ON  MORTAR  AND  CEMENTS. 


cement,  however,  will  get  Lot  in  consequence  of  the 
rapid  chemical  action  which  takes  place.  Still,  there 
exist  also  limits  in  regard  to  slow-setting.  If  it  sets 
too  slowly,  it  remains  resistless,  and  is  pressed  out  of 
the  joints,  for  which  reason  the  continuation  of  the 
work  will  be  prevented  until  the  mass  is  sufficiently 
hardened. 

If  once  set  under  water,  the  cement  should  continu- 
ally get  harder  without  changing  its  volume,  cracking, 
or  perhaps  even  falling  to  pieces.  The  cement  should 
completely  fill  the  mould  in  which  it  has  been  pre- 
pared as  thick  paste  ;  it  should  not  suifer  any  contrac- 
tion by  the  evaporation  of  water  added  in  surplus. 
On  the  other  hand,  there  should  be  no  increase  of  vol- 
ume by  swelling. 

Hydraulic  Mortar  from  American  Limestone. 

These  limestones  contain  mostly  lime,  silica,  alu- 
mina, oxide  of  iron  and  magnesia,  which  form  the 
proper  materials  for  the  preparation  of  mortars  ;  they 
will  withstand  the  action  of  water  and  moisture  better 
in  proportion,  as  the  quantity  of  silica,  alumina  and 
magnesia  is  larger ;  they  contain  40  per  cent,  carbon- 
ate of  lime,  30  per  cent,  carbonate  of  magnesia,  and 
20  per  cent,  silica,  the  balance  is  alumina  and  oxide 
of  iron,  and  they  form  a  good  mortar  and  a  good 
building  material ;  but  when  the  magnesia  is  too  pre- 
valent, will  deteriorate  it  for  building  purposes,  it 
being  too  friable.  The  dolomite,  Avhich  is  also  called 
bitterspar,  a  magnesian  limestone,  is  a  double  carbon- 
ate of  lime  and  magnesia,  and  abundant  in  the  United 
States,  is  a  granular  limestone,  and  a  hardness  of  3.  5, 


ON  MORTAIl  AND  CEMENTS. 


43 


a  spec.  gr.  of  3.1,  and  consisting  of  70  per  cent,  lime 
and  nearly  40  per  cent,  of  magnesia  and  some  oxide  of 
iron  and  manganese  ;  is  unfit  by  itself  as  a  building 
material,  having  a  great  tendency  to  crumble  into 
small  fragments,  and  forms  likewise  an  inferior 
material  for  burning  and  converting  it  into  cement, 
because  it  lacks  the  silica  indispensable  for  this  pur- 
lose.  By  an  addition  of  an  alkaline  silicate,  either 
the  silicate  of  potash  or  soda,  and  an  addition  of  some 
alumina,  will,  after  burning,  produce  a  good  hydraulic 
cement,  particularly  in  such  localities  where  no  good 
native  hydraulic  limestone  is  found.  Not  alone 
France  and  Germany  are  particularly  rich  in  deposits 
of  hydraulic  lime,  and  in  the  United  States  likewise, 
but  these  in  our  neighborhood  may  be  particularly 
mentioned  at  Rondout,  on  the  western  shore  of  the 
Hudson  River,  100  miles  distant  from  New-York. 
The  quarrying  in  those  subterranean  rocks  for 
hydraulic  cement,  and  also  common  limestone  is  car- 
ried on  in  that  region,  along  a  large  extent  of  the 
valley  of  the  Rosedale  River  ;  through  this  valley  the 
Hudson  and  Delaware  Canal  is  constructed,  which 
brings  the  coal  from  the  Lackawanna  valley  at  Car- 
bondale  directly  to  to  the  Hudson  River.  This  coal 
being  a  very  pure  anthracite,  is  admirably  adapted 
for  use  in  the  limestone  and  cement  furnaces  situated 
at  the  junction  of  this  canal  with  the  Hudson  River. 

In  burning  hydraulic  limestone,  not  only  the  car- 
bonic acid  and  water  of  hydration  are  drawn  off,  as  is 
the  case  with  common  limestone,  but  after  the  lime 
and  magnesia  have  parted  with  their  carbonic  acid,  at 
the  high  temperature  of  the  furnace,  they  act  on  the 


ON  MOHTAR  AND  CEMENTS. 


silica  and  alumina,  as  it  were,  like  two  powerful  bases, 
and  a  silicate  of  lime  and  magnesia,  as  also  silicate  oi 
alumina  and  aluminate  of  lime,  are  formed.  Tlie  ex- 
act chemical  reaction  during  the  burning  process  is, 
however,  as  yet  not  well  understood,  and  undoubtedly 
varies  in  different  limestones,  according  to  their 
chemical  constitution,  which  latter  appears  also  to 
vary  considerably,  but  without  affecting  materially 
their  useful  properties. 

In  regard  to  the  theoretical  causes  of  the  hardening 
process,  which  takes  place  under  water,  it  may  be  re- 
marked that  this  curious  and  interesting  phenomenon, 
being  of  an  entirely  chemical  nature,  has  largely 
drawn  towards  itself  the  attention  of  eminent  chemists, 
who  have  attempted  to  explain  it  in  accordance  with 
well  known  chemical  laws.  All  hydraulic  limestones 
may,  by  the  ordinary  method  of  analysis,  be  decom- 
posed into  two  component  parts  ;  the  one  consisting 
of  the  carbonates  of  the  earth,  such  as  lime,  magnesia, 
etc.,  which,  like  ordinary  limestones,  jdeld  a  fat  lime  ; 
the  other,  a  silicate,  or  rather  a  mixture  of  the  sili- 
cates of  alumina,  magnesia,  lime,  and  sometimes  po- 
tassa,  as  we  find  in  the  felspar,  which  is  a  silicate  of 
alumina  and  potash,  and  a  greater  or  less  excess  of 
free  silica  ;  the  latter  constituent  is,  therefore,  simply  a 
kind  of  clay.  The  reaction  during  the  burning  pro- 
cess has  been  already  alluded  to.  Now,  when  freshly 
burnt  cement  is  mixed  with  water,  the  excess  of  caus- 
tic lime  as  well  as  the  compound  into  which  the 
silicious  clay  has  been  converted  during  the  burning, 
react  upon  one  another  in  such  a  manner,  that  a  solid' 
stone-like  silicate  is  produced  in  the  humid  way,  the 


ON  MOHTAR  AND  CEMENTS. 


45 


water  has  a  double  action  ;  dry  substances,  such  as 
lime  and  silicate  of  alumina,  do  not  act  one  upon 
another,  unless  the  solvent  power  of  water  is  brought 
into  play  so  as  to  bring  them  into  close  contact ;  the 
water  transfers  continually  the  lime  it  dissolves  to  the 
siHca.  The  absolute  necessity  of  keeping  such  mor- 
tar under  water,  in  order  to  have  it  harden,  is  thus 
explained.  Another  action  of  the  water  is  this  :  it 
enters  into  a  state  of  hydration  in  the  silicate  of  lime 
as  soon  as  formed.  It  must  also  be  observed,  that  the 
molecular  condition  of  the  silica  is  of  the  utmost  im- 
portance in  this  process.  Fine  sand  will  not  combine 
with  lime,  when  the  latter  is  dissolved  in  water  that  is 
in  a  form  known  under  the  name  of  limewater  ;  but 
silica,  precipitated  from  a  soluble  glass  solution  by 
means  of  an  acid,  which  produces  the  gelatinous  form 
of  silica,  will  at  once  combine  with  the  lime  in  lime- 
water  and  form  a  siHca  of  lime.  The  silica  in  the 
hydraulic  mortar  is  also  in  a  state,  not  like  fine  sand, 
but  chemically  combined  and  dissolved  in  the  mass, 
and  therefore  ready  to  combine  with  the  lime  in  lime- 
water.  Next  in  importance  to  silica  is  the  magnesia, 
which  renders  the  lime  hydraulic,  which,  according  to 
Fuchs,  has  been  proved  that  lime  and  magnesia,  well 
mixed  will  harden  under  water  to  a  certain  extent 
without  the  addition  of  silica  ;  for  we  have  in  Ger- 
many a  hydraulic  lime  containing  only  4  per  cent. 
When  silica  is  found  to  the  extent  of  52  per  cent,,  the 
point  of  saturation  is  reached,  and  such  limestone  is 
no  more  hydraulic.  Alumina  and  iron  may  be  en- 
tirely absent,  although  the  foi'mer  is  always  present  in 
the  best  kinds  of  hydraulic  mortars,  of  which  that  of 


46 


ON  MORTAE  AND  CEMENTS. 


Eondout,  usuaflly  called  Eosedale  cement,  and  with 
tlie  employment  of  which  the  Croton  Water  Works  of 
New -York  City  were  built,  is  the  best  on  this  conti- 
nent. 

It  is  confidently  to  be  hoped,  that  by  the  proper  ap- 
plication of  alkaline,  silicates  will  contribute  much  to 
the  manufacture  of  an  artificial  hydraulic  cement. 

Gekman  Hydraulic  Cement. 

This  material,  artificially  prepared,  is  in  great  use, 
and  is  of  very  peculiar  composition ;  unquestionably 
it  is  intended  to  form  a  silicate-aluminate  of  lime,  or, 
in  other  words,  an  argillaceous  silicate,  but  the  admix- 
ture, such  as  charcoal  and  iron  filings,  cannot  be  ex- 
plained, but  the  base  being  obtained  by  the  produc- 
tion of  an  alkaline  silicate,  bespeaks  for  it  a  useful 
vehicle  as  a  cement. 

It  is  prepared  with  25  parts  common  clay,  60  parts 
lime,  10  parts  magnesian  limestone,  10  parts  iron  fil- 
ings, and  10  parts  of  black  oxide  of  manganese  ;  these 
materials,  in  very  fine  powders,  are  made  plastic  by 
the  liquid  silicate  of  soda,  at  once  applied  as  a  ce- 
ment or  mortar,  but  it  will  not  set  at  once,  six  hours 
being  required  for  the  mass  to  harden. 

Stinde  proposes  the  silicate  as  a  very  useful  cement, 
by  mixing  equal  parts  of  oxide  of  manganese  and 
oxide  of  zinc,  and  making  them  into  a  thinish  paste 
with  the  silicate  of  soda,  which  paste,  quickly  applied, 
sets  very  rapidly  ;  and  by  mixing  the  hydrauhc  lime 
to  this  composition,  it  is  a  cement  which  will  resist 
permanently  also  the  action  of  water  and  heat. 


ON  MORTAR  AND  CEMENTS. 


47 


"Cement  and  Mortar  of  the  Ancients. 

We  all  know  how  entlmsiastic  some  are  in  tlieir 
praises  of  those  ancient  structures  which  have  resisted 
for  ages  the  ravages  of  time.  They  imagine  that  they 
are  at  liberty  to  draw  conclusions  which  are  not  the 
most  favorable  to  the  architecture  of  the  present  time. 
Although  they  may  be  in  a  measure  correct,  it  can- 
not be  denied  that  such  critics  are  too  partial  in  their 
admiration  for  things  ancient  as  opposed  to  things 
modern.  We  frequently  hear  the  remark  that  some 
of  the  Eoman  mortars  have  endured  for  eighteen  cen- 
turies the  vicissitudes,  of  time,  while  many  buildings 
of  now-a-days  present,  in  a  very  brief  period,  the  sign 
of  quick  decay  ;  but  they  forget  that  these  ancient 
buildings  constitute  an  exceedingly  small  fraction  of 
the  enormous  number  of  those  erected  during  many 
centuries  in-  Egypt,  Greece,  Rome  and  her  provinces. 
They  do  not  consider  that  thousands  of  temples,  pal- 
aces, and  private  dwellings  have  been  entirely  de- 
stroyed. And  what  answer  can  they  assign  to  the 
fact  that  the  very  complaints  they  indulge  in  were 
even  more  frequent  then  than  now  ?  Pliny  asserts 
that  the  reason  of  the  falling  in  of  many  buildings  in 
Rome  was  to  be  attributed  to  the  fact  of  the  bad 
quality  of  the  mortar. 

"  Still  more  important  than  this  argument  is  that 
of  Yitruvius,  the  architect  of  Augustus.  He  has  left 
a  work  on  Roman  architecture  in  which  we  find  noth- 
ing that  entitles  us  to  place  the  architects  of  antiquity 
above  those  of  the  present  time.  Again,  it  has  not 
been  taken  into  account  that  a  great  part  of  the  ex- 
traordinary strength  of  antique  architecture  is  more 


48 


ON  MORTAR  AND  CEMENTS. 


the  effect  of  time  than  the  mechanical  skill  of  the 
builder,  or  the  virtues  of  his  cements,  as  we  propose 
to  show  hereafter.  Pliny  and  Yitruvius  both  explain, 
to  the  best  of  their  knowledge,  what  kind  of  materials 
the  builders  selected  for  their  cements,  and  how  they 
were  prepared.  The.  process  was  identical  with  the 
modern  modus  operandi.  It  is  true  that  the  old  Ro- 
mans were  particularly  careful  in  the  selection  of  ma- 
terials for  their  mortar,  as  well  as  in  its  preparation. 
They  were  aware  that  they  must  calcine  the  lime- 
stone, and  mix  it  with  sand,  in  order  to  apply  it ;  but 
did  not  possess  any  correct  idea  of  the  change  which 
limestone  undergoes  in  the  process  of  calcination,  nor 
of  that  which  is  the  cause  of  the  cohesive  quality  of 
mortar. 

"  Many  centuries  elapsed  before  these  facts  were 
understood  and  explained.  Black,  in  1757,  started 
the  explanatory  theory  by  the  discovery  of  carbonic 
acid.  A  few  years  previous  to  this,  Marggraf,  the 
discoverer  of  sugar  in  beets,  found  the  elements  of 
gypsum,  which  was  already  employed  by  the  Komans  ; 
and,  in  1768,  Lavoisier  demonstrated  the  causes  of  the 
hardening  of  burnt  gypsum  when  it  is  mixed  with 
water. 

[  "  The  ancients,  therefore,  put  their  practical  know- 
ledge to  the  best  possible  account.  As  they  were  de- 
ficient in  chemical  knowledge,  •  they  were  guided  only 
by  what  observation  taught  them.  Their  chief  care 
was  centred  in  the  exterior.  In  the  selection  of  lime- 
stone, the  color  decided.  The  white  ones  were  con- 
sidered best,  and  the  colored  ones  were  seldom  used. 
Those  taken  from  the  interior  of  the  earth  were  pre- 


ON  MORTAR  AND  CEMENTS. 


49 


ferred  to  the  stones  wliicli  were  met  with  upon  the 
shores  of  rivers.  A  law  provided  that  the  Hme  must 
have  been  slaked  three  years  before  it  could  be  used. 
The  same  also  prescribed  the  quantity  of  sand  which 
must  be  mixed  with  the  lime,  mentioning  also  that 
crushed  cherts  imparted  a  greater  strength  to  the 
mortar.  Its  preparation  was,  as,  it  were,  a  state  af- 
fair, the  censors  watching  carefully  over  it.  In  spite 
of  all  this,  it  often  happened,  as  Pliny  states,  that 
they  did  not  attain  the  object  in  view. 

"  But  in  the  advance  of  chemical  science,  the  fact 
has  been  established  that  a  mortar  can  be  prepared 
that,  in  the  course  of  one  or  two  years,  will  be  as 
strong  and  durable  as  Roman  mortar  after  the  lapse 
of  two  thousand  years.  The  builders  of  the  ancients 
were  not  farther  advanced  than  those  of  the  middle 
ages.  The  wall's  of  the  Bastile,  for  instance,  were  so 
strong  that  they  had  to  be  blasted  away.  This  had 
likewise  to  be  done  in  the  removal  of  the  remnants  of 
a  bridge  at  Agen,  built  about  the  year  1200 ;  and  the 
mortar  of  a  bridge  erected  at  Calhours  in  1400  was 
even  found  to  be  considerably  stronger  than  that  of 
the  antique  theatre  of  the  same  city. 

"  The  Bomans  were  also  acquainted  with  hydraulic 
cement.  The  merit  of  this  knowledge  is,  however, 
considerably  lessened,  when  we  consider  that  the  same 
is  found  in  the  volcanic  districts  of  Southern  Italy.  A 
mere  accidental  observation,  the  same  being,  perhaps^ 
mixed  with  sand  instead  of  lime,  may  have  led  to  its 
application.  Says  Yitruvius  :  '  There  exists  a  kind  oi 
dust  which  produces  strange  things ;  it  is  found  near 
Baja  and  the  Vesuvius.    When  mixed  with  lime,  it 


50 


ON  MORTAR  AND  CEMENTS. 


forms  a  mortar  wliicli  not  only  imparts  great  strength 
to  buildings,  but  also  to  water-works.' 

"  The  natural  cement  in  question  is  a  volcanic 
pumice-stone,  like  breccia,  which  is  still  found  in  the 
I  .environs  of  Naples.  At  a  less  remote  period  of  time, 
when  the  Eomans  invaded  the  valleys  of  the  Lower 
Bhine,  they  easily  recognized  the  volcanic  nature  of 
the  Brolil  Yalley.  Here,  as  well  as  amid  the  surround- 
ings of  the  beautiful  Laacher  Lake,  which  lies  like  a 
jewel  set  in  the  midst  of  the  long-extinct  Hhenish 
volcanoes,  they  discovered  another  natural  cement — 
the  trass — in  such  considerable  quantities,  that  the 
quarries  which  were  opened  at  that  time  are  still  in 
existence.  The  use  of  hydraulic  cement  in  ancient 
times  could,  therefore,  have  been  only  a  limited  one, 
as  it  w^as  found  only  at  the  two  places  mentioned. 
Its  artificial  preparation  was  not  understood.  The 
solution  of  this  problem  was  reversed  for  the  investi- 
gating minds  of  the  present  progressive  century." 

"  The  Uses  of  Hydraulic  Cement. 

"  It  is  justly  esteemed  far  superior  to  metal  for  the 
lining  of  cisterns,  the  water-proofiDg  of  cellar  bot- 
toms, and  similar  purposes.  A  few  directions  for  its 
preparation  and  use  may  not  be  out  of  place.  To 
make  water-proof  work,  it  must  be  borne  in  mind 
that  common  lime  must  not  be  used  at  all ;  for  on  com- 
mon lime,  water  or  moisture  has  an  effect  just  the 
opposite  to  that  which  it  has  on  the  water  lime,  ren- 
dering it  soft  and  quite  friable  when  dried  ;  whilst  on 
the  water  lime  the  well-known  effect  is  to  make  it 


ON  MORTAIl  AND  CEMENTS. 


51 


perfectly  hard.  No  mixture  of  these  two  varieties  of 
Kme  can,  therefore,  be  made  under  water.  But, 
although  they  do  not  act  well  together  even  under 
ground,  they  serve  well  in  dry  places,  such  as  build- 
ings whose  walls  are  of  extra  thickness  ;  and  if  proper 
care  be  taken,  they  will  conjointly  form  a  ver^^  com- 
pact and  powerful  cement.  The  fact  that  water  Kme 
shrinks  when  wet,  while  common  lime,  in  the  same 
state,  swells,  at  once  points  out  the  manner  of  treat- 
ment to  be  pursued  in  uniting  the  two  thoroughly. 
Thus,  it  is  necessary  to  ascertain  the  percentage  of 
shrinking  of  the  one  and  increase  in  the  other,  as 
nearly  as  possible,  before  the  proportion  of  one  to  the 
other  can  be  determined,  A\dtli  a  view  to  their  inti- 
mate combination.  Such  experiments  are  the  more 
necessary  when  we  consider  the  great  difference 
which  exists  in  the  quality  of  both  kinds  of  lime  in 
various  localities.  The  simplest  and  most  effectual 
mode  of  testing  water  lime  is  to  put  several  portions 
of  different  makes  into  small  bags  of  flannel,  and 
throw  them  into  a  basin  of  water.  After  three  min- 
utes' immersion,  take  them  all  out  at  once,  and 
squeeze  each  in  the  hand.  Then  take  off  each  bag, 
and  that  which  is  best  is  firmest,  and  when  thrown 
naked  into  the  water  again,  loses  least  of  its  outer 
cast.  If  none  of  them  will  bear  uncovering  at  three 
minutes,  try  four,  five  minutes,  but  this  latter  should 
be  the  longest  test.  The  test  for  common  lime  is,  on 
the  contrary,  the  bursting  open  and  evolving  of  caloric 
in  a  greater  or  less  degree  ;  and  the  consequent  action 
of  the  water  will  show,  by  its  bubbles,  the  power  of 
the  lime. 


52 


ON  MORTAR  AND  CEMENTS. 


"  It  is  the  percentage  of  claj  contained  in  any 
specimen  of  lime  that  determines  the  solidifying  pro- 
perty of  the  cement  made  from  it.  The  best  hydraulic 
lime  contains  silex,  lime  and -magnesia,  or  alumina. 
Its  solidification  is  attributable  to  the  formation '  of 
silicate  of  alumina  and  lime,  or  of  magnesia  and 
lime,  which  combines  with  water,  and  produces  a  hy- 
drate excessively  hard  and  insoluble  in  water.  The 
hardening  of  hydraulic  lime  may,  then,  be  compared 
to  that  of  calcined  plaster,  which  also  combines  with 
water  to  form  a  solid  hydrate  ;  which  calcined  plaster, 
from  the  large  quantities  of  it  manufactured  near 
that  city,  is  commonly  known  as  Plaster  of  Paris.  A 
limestone  containing  thirty  per  cent,  of  clay  makes  a 
quick-setting  cement ;  and  we  have  in  the  United 
States  the  Kosedale  and  the  Belleville  cements,  hav- 
ing forty  and  fifty  per  cent.  They  become  exceed- 
ingly hard  when  plunged  in  water  for  from  two  to 
three  minutes.  Both  these  cements,  especially  the 
former,  have  been  used  extensively  by  our  engineers. 

"  Inferiority  in  the  quality  of  hydrauHc  lime  may 
be  produced  by  the  want  of  proper  care  during  its 
manufacture,  the  stone  being  calcined  at  too  high  a 
temperature  ;  the  double  silicate  in  such  case  becom- 
ing a  sort  of  frit  J  which  does  not  hydrate  in  contact 
with  water. 

"As  hydraulic  lime  is  expensive  according  to  the 
distance  of  its  transportation,  we  will  here  give  the 
method  of  making  an  artificial  hydraulic  lime,  accord- 
ing to  the  highly  successful  experiments  of  M.  Yicat, 
a  celebrated  French  engineer,  and  the  author  of  a 
much  esteemed  work  on  hydraulic  cement,  who  first 


ON  MORTAR  AND  CEMENTS. 


53 


showed  the  method  to  be  adopted  in  its  formation 
It  is  prepared  by  stirring  into  water  a  mixture  of  one 
part  of  clay  and  four  parts  of  chalk  ;  these  materials 
should  be  mixed  by  a  vertical  wheel  turning  in  a  cir- 
cular trough,  and  made  to  flow  out  into  a  large 
receiver.  A  deposit  soon  takes  place,  which  is  formed 
into  small  bricks,  which,  after  being  dried  in  the  air, 
are  moderately  calcined.  Hydraulic  lime  thus  pre- 
pared enlarges  about  two- thirds  in  volume  when 
placed  in  water.  Like  the  natural  hydraulic  lime,  it 
can  be  completely  dissolved  by  acids.  This  invention 
of  artificial  hydraulic  lime  has  rendered  Vicat  deserv- 
edly famous,  as  it  has  been  in  use  for  many  years  in 
the  public  works  throughout  France,  and  was  even 
employed  in  the  hydraulic  masonry  of  the  St.  Martin 
Canal.  That  it  can  be  made  in  this  country,  there  is 
no  doubt,  as  the  argillaceous  or  potter's  clay  required 
is  to  be  found  almost  everywhere. 

The  new  cement  which  M.  Sorel  proposed  to  the 
French  Academy  consists  in  the  application  of  basic 
hydrated  oxychloride  of  magnesium,  may  unquestion- 
ably be  improved  by  means  of  a  silicated  hydraulic 
lime  and  the  bittern  of  the  salines,  which  is  a  chlo- 
ride of  magnesium  in  a  concentrated  condition. 

Many  important  facts  have  come  to  light  by  the 
investigations  made  on  hydraulic  limes  and  artificial 
stones,  which  prove  that  a  considerable  qua  itity  of 
})otash  is  contained  in  the  natural  hydraulic  and  other 
cements ;  the  origin  of  which  is  attributed  to  the 
decomposition  of  the  alkaline  silicates  by  the  lime, 
and  this  may  be  proved  by  the  formation  of  saltpetre 
or  nitrate  of  potash  in  the  efiiorescences  of  walls  and 


54 


ON  MORTAR  AND  CEMENTS. 


earths  in  caves,  called  an  eremacausis  of  substances 
which  contain  nitrogen,  and  form,  therefore,  ammo- 
nia, and  in  contact  with  porous  substances  undergo 
an  oxydation  and  conversion  into  nitric  acid,  and  at 
once  is  combined  with  the  alkalies  contained  in  the 
native  lime  occurring  in  the  older  formations,  and  was 
separated,  under  certain  circumstances,  from  the  al- 
kaline silicates  found  in  those  limestones — nitrate  of 
potash  the  result.    In  general  terms,  nitre,  or  nitrate 
of  potash,  which  is  found  in  crusts  on  the  surface  of 
the  earth,  on  walls  and  rocks,  and  in  caves,  is  found 
in  those  localities  in  certain  soils  of  Spain,  Egjp^t, 
Persia  and  East  Indies,  especially  in  hot  weather 
succeeding  rains ;  it  is  also  manufactured  from  soils 
where  other  nitrates  (nitrate  of  lime  or  nitrate  of 
soda)  form  in  a  similar  manner,  and  beds  called  nitra- 
ries  are  arranged  for  this  purpose  in  many  countries. 
Hefuse  animal  matter  also,  putrified  in  calcareous 
soils,  gives  rise  to  nitrate  of  lime,  as  we  find  it  so  fre- 
quently in  cow  and  horse  stables,  and  is  then  con- 
verted into  nitrate  of  potash  ;  old  plaster  walls,  when 
lixiviated,  afford  about  5  per  cent,  of  nitre.    It  is 
known  that  nitre  requires  for  its  formation  dry  air  and 
long  periods  without  rain  ;  the  potash  comes  mainly 
from  the  debris  of  felspathic  and  lime  rocks  in  the 
soil,  or  in  the  cements,  if  they  have  been  used  for 
building  walls,  and  the  oxydation  of  the  nitrogen  of 
the  air  is  promoted  by  organic  matters,  hence  the 
nitre  is  generally  associated  with  azotized  decomposed 
organic  substances.    A  nitre  crust  from  the  vicinity 
of  Constantine,  Algeria,  afforded  Boussingault  85  per 
cent,  nitrate  of  potash,  with  some  nitrate  of  lime, 


ON  MORTAR  AND  CEMENTS. 


55 


soda  and  magnesia.  In  the  Mammoth  Cave  of  Ken- 
tucky, where  the  nitre  is  found  scattered  through  the 
loose  earth  in  great  abundance,  and  was  utilized  dur- 
ing the  war  of  1812,  also  in  the  Mississippi  Valley, 
in  Missouri,  many  caves  have  yielded  the  nitre  which 
was  of  great  use  to  the  Secessionists  of  the  late  war, 
when  Tennessee,  along  the  limestone  slopes  and  in 
the  gorges  of  the  Cumberland  table  land,  produced  a 
large  amount  of  saltpetre. 

The  nitrate  of  soda,  formed  in  a  similar  manner 
like  that  of  nitrate  of  potash,  but  more  particularly 
is  found  in  the  dry  pampas  of  Chili,  where  it  is  found 
at  a  height  of  3,300  feet  above  the  sea,  contains  beds 
of  several  feet  in  thickness,  along  with  gypsum,  com- 
mon sail,  glauber  salt,  and  the  remains  of  recent 
shells,  indicating  the  former  presence  of  the  sea. 

Respecting  the  cement  which  is  formed  by  the 
moist  way,  it  is  a  fact  that  when  chalk  is  brought  in 
contact  with  solutions  of  alkaline  silicates,  an  ex- 
change of  the  acids  of  both  salts  takes  place,  one 
part  of  the  chalk  is  converted  into  silicate  of  lime, 
and  the  corresponding  quantity  of  potash  in  carbon- 
ate of  potash  ;  this  explains  the  true  artificial  stone, 
which  has  become,  on  exposure  to  the  atmosphere,  so 
hard,  that,  if  the  mixture  contains  a  sufficient  quan- 
tity of  a  silicate,  possesses  the  property  to  adhere 
firmly  to  such  bodies  where  it  has  been  applied,  the 
materials  so  formed  with  the  silicate  of  potash  or 
soda  are  analogous  to  cements  without  burning,  and 
may  be  used  for  restoring  monuments,  etc.  In  the 
silicification  of  artificial  stones,  the  affinity  of  lime  to 
the  silica  contained  in  the  soluble  glass  is  manifest, 


56 


ON  MORTAK  AND  CEMENTS. 


and  shows  the  effect  of  the  alkahne  silicates  on  lime- 
stones ;  and  how  the  influence  of  the  atmosphere  in 
the  hardening  of  silicates  or  artificial  limes  is  brought 
to  bear  through  the  atmospheric  carbonic  acid  by  the 
separation  of  one  part  of  silica  in  the  silicates,  and 
how  the  other  parts  of  the  silicates,  when  in  close 
contact  with  a  sufficient  quantity  of  carbonate  of 
lime,  a  lime  silicate  is  formed. 

This  acquired  knowledge  has  produced  numerous 
applications  in  industry  ;  it  has  proved  that,  by  arti- 
ficial impregnation  of  mineral  substances  into  the 
interior  of  porous  substances,  organic  as  well  as 
inorganic  matters  are  preserved  or  silicified.  The 
silicificiition  of  fine  sandstone  is  easily  effected  by  the 
mixture  of  1  part  of  liquid  silica,  and  2  parts  of  fine 
sand,  with  the  addition  of  a  small  quantity  of  chalk 
and  whits  clay,  all  of  which  are  wrought  into  a  paste, 
and  then  formed  into  desired  objects  and  exposed  to 
the  atmosphere  for  some  time,  and  the  finishing  pro- 
cess continued^  by  means  of  hj^draulic  pressure  and 
heating  in  hot  chambers,  the  particulars  of  which 
have  been  indicated  in  a  former  chapter.  It  has  been 
ascertained  that  always,  if  any  salt  insoluble  in  water 
is  brought  in  contact  with  the  solution  of  a  salt  which 
forms  with  the  acid  of  the  base  of  the  insoluble  salt 
a  less  soluble  substance,  an  exchange  takes  place, 
which,  although  but  partial  sometimes,  produces  the 
formation  of  double  salts.  This  discovery  led  to  a 
direct  application  that  white  lead,  chromate  of  lead, 
chromate  of  lime,  and  the  majority  of  the  carbonated 
metallic  salts,  are  suitable  for  silicification. 


SILICATE  PAINTING. 


57 


SILICATE  PAINTING. 

.  Wood  may  be  painted  by  covering  it  first  witli  a 
chalk  ground,  which  must  be  thick  enough  to  allow  a 
polishing  with  pumice  ;  to  chalk,  glue  or  a  little  sili- 
cate solution  may  be  added,  as  a  binding  material. 
Another  difficulty  occurs  after  the  first  has  been  over- 
come, in  the  oozing  out  of  the  carbonate  of  potash  in 
damp  weather,  until  the  whole  salt  has  been  expelled, 
and  many  experiments  have  failed,  and  hydrochlorate 
of  ammonia  was  first  proposed  in  a  weak  solution,  and 
an  absolute  insolubility  of  the  color  was  thereby  ob- 
tained, but  chlorate  of  potash  remained  in  this  opera- 
tion, which  destroys  the  gloss  of  the  colors  if  not  at 
once  removed  by  repeated  washing  ;  forced  to  resort 
to  those  few  chemical  agents,  apt  to  fix  the  potash, 
which  should  enter  as  insoluble  combinations  in  the 
color  without  destroying  them,  the  perchloric  and 
hydrofluoric  acids  were  resorted  to.  It  is  well  known, 
that  by  washing  with  hydrofluoric  acid  the  density  of 
the  colors  is  much  increased,  and  it  was  thought, 
therefore,  safe  to  use  it,  particularly  in  painting  on 
glass,  but  only  as  a  very  weak  solution.  Hydrofluoric 
acid  possesses  the  most  remarkable  property  to  dis- 
solve most  oxides  when  in  a  concentrated  state.  The 
application  of  the  weak  solution  of  hydrofluoric  acid, 
either  for  fixing  the  potash  in  painting  and  in  silicifi- 
cation  of  limestone,  was  mainly  c^ilculated  for  such 
case  where  a  silicate  has  been  used  witli  an  excess  of 
potash  ;  and  in  hardening  of  soft  an-l  porous  lime- 
stones be  a  partial  conversion  into  a  lime  silicate,  it 
was  found  very  expedient  for  fixing  the  potash,  and 


58 


SILICATE  PAINTING. 


making  sure  the  insolubility  to  moisten,  at  first  with 
a  weak,  and  then  strong  solution  of  the  hydrofluoric 
acid,  the  stones  when  the  potash  oozed  out.  The 
acid,  however,  penetrates  the  stone  and  produces  an 
insoluble  compound  ;  in  other  words,  it  fixes  the 
soluble  potash,  and  produces  an  insoluble  compound. 
Through  this  discovery  hydrofluoric  acid  was  found  a 
Very  useful  application  in  the  fluosilicated  lime.  * 

If  brought  in  contact  with  lime,  hydrofluoric  acid  is 
capable  of  dissolving  it  considerably  without  produc- 
ing an  immediate  precipitate  of  calcium,  or  a  separa- 
tion of  the  silica  ;  but  at  a  certain  state  of  saturation 
any  addition  of  lime  decomposes  entirely  the  hydro- 
fluoric acid,  and  so  much  that  not  a  trace  of  these 
bodies  can  be  discovered  in  the  fluid.  The  same  re- 
sults are  obtained  by  the  carbonate  of  lime,  instead 
of  the  caustic  lime,  and  that  silicium  and  fluor  are 
produced  in  the  limestone,  which  hardens  but  slowly, 
and  it  is  therefore  simply  a  fluorsihcon  that  produces 
the  hardening  of  the  lime.  The  effect  of  the  hydro- 
fluoric acid  on  gypsum  is  also  produced  in  both  mix- 
ing, the  surface  of  the  gypsum  is  considerably  har- 
dened. If,  however,  the  acid  is  used  in  excess,  the 
gypsum  is  covered  with  raised  pustules,  which  owe 
their  existence  to  the  formation  of  bisulphate  of  lime, 
because  sulphuric  acid  does  not  act  as  well  as  the  car- 
bonic acid  in  the  treatment  of  limestone  ;  a  fluor-cal- 
cium,  mixed  with  soluble  glass,  may  be  used  as  a 
paint,  or  paste,  or  a  cement,  or  any  coating  of  other 
substances,  and  becomes  so  hard  and  weatherproof 
that  neither  soda  nor  potash  will  detach  from  the 
combination,  and  will  remain  drv. 


SILICATE  PAINTING. 


69 


Painting  on  Metals,  Glass  and  Porcelain. 
Silica  painting  adheres  strongly  on  metals,  provided 

care  is  taken  to  keep  the  substances  some  time  from 
the  contact  with  water.  The  most  durable  paint  is 
produced  on  zinc,  also  on  porcelain  and  glass  ;  the 
colors  assume  a  semi -transparency  if  painted  on  glass, 
and  no  doubt  afford  much  inducement  for  its  use. 
The  sulphate  of  baryta,  artificially  prepared,  combined 
with  silicate,  applied  to  glass,  makes  a  milliy  white 
appearance,  and  is  very  beautiful,  as  it  incoporates 
very  intimately  with  the  silica,  so  that  after  the  lapse 
of  a  few  days  the  paint  cannot  be  removed  even  with 
warm  water.  If  this  glass  is  exposed  to  high  heat, 
(6^  Wedgewood),  a  fine  white  enamel  is  formed  on  the 
surface,  which  will  compare  well  with  the  oxide  of  tin, 
and  is  much  cheaper.  Ultramarine,  oxide  of  chrome, 
if  converted  into  enamels,  form  a  prolific  source  for 
the  new  art  of  painting.  It  is  not  quite  necessary 
that  a  chemical  combination  should  be  produced  in 
all  these  colors,  if  they  only  adhere  strongly  and  pro- 
duce the  silicated  cement,  which  has  become  hard  by 
its  fine  division  and  easy  admission  of  air. 

Emery,  sesquioxide  of  iron  and  peroxide  of  man- 
ganese, if  finely  powdered  and  prepared  with  a  con- 
centrated solution  of  .soluable  glass,  produce  cements 
of  extraordinary  hardness,  resisting  the  effect  of  heat 
completely,  and  become  perfectly  insoluble  in  water. 

For  the  production  of  an  indestructible  ink,  soluble 
glass  has  been  used  and  obtained  by  mixing  finely 
burnt  lampblack  with  the  liquid  soluble  glass.  Bra- 
connot's  ink  is  prepared  by  decomposing  leather  in 
caustic  potash,  and  adding  to  the  black  mass  the 


60 


SILICATE  PAINTING. 


liquid  soluble  glass.  A  decoction  of  cochineal  mixed 
with  the  liquid  soluble  glass,  produces  a  red  ink,  re- 
sisting completely  the  action  of  chlorine  and  all  other 
acids. 

Stereo-chromic  for  Easel  Painting. 

The  basis  for  this  class  of  painting  may  be  made 
from  plates  of  burnt  porous  clay  ;  it  is  first  impreg- 
nated sufficiently  with  liquid  soda  glass.  These  plates 
may  be  three-fourths  of  an  inch  thick ;  after  one  or 
two  applications  they  become  as  hard  as  any  stone 
ware ;  they  are  very  suitable  for  painting  ground. 
The  Uthographic  stone  makes  a  good  base  for  easel 
painting  ;  a  thin  coating  of  liquid  glass  mortar  will 
produce  a  good  base,  and  it  maybe  first  moistened 
with  phosphoric  acid,  which  assists  much  to  absorb 
the  colors  with  the  liquid  glass,  and  to  make  them 
fast. 

The  colors  to  be  used  for  this  class  of  painting 
ought  not  to  be  chosen  which  decomposes  the  liqtiid 
glass,  such  as  contain  strong  acids,  nor  those  from 
organic  substances.  Burnt  oxides  are  better  than 
raw  oxides,  vermihon  becomes  brown,  and  at  last 
black  ;  cobalt  blue  becomes  clearer  with  the  liquid, 
and  the  yellow  ochre  becomes  darker. 

All  colors  ought  to  be  properly  prepared  to  make 
them  fit  for  the  silica  painting,  such  as  the  great 
variety  of  oxides  ;  many  of  which  may  be  suitable, 
also  chrome  red,  ultramarine,  umber,  baryta  white, 
cadmium  yellow,  and  many  more,  purposely  made  by 
some  chemists,  not  containing  free  acid,  which  enter 
into  a  decomposing  chemical  combination. 


SILICATE  PAINTING. 


61 


The  permanent  white,  or  artificial  sulphate  of  baryta, 
is  said  to  be  the -proper  material  for  a  white  paint„  It 
is  obtained  from  the  native  minerals,  heavy  spar  or 
sulphur  of  baryta,  and  witherite  or  carbonate  of  baryta, 
The  manufacture  of  the  new  paint  is  effected  by  the 
reduction  of  the  native  sulphate  to  a  chloride  of 
barium,  or  dissolving  the  native  witherite  in  hydro- 
chloric acid,  and  then  adding  either  sulphuric  acid  or 
glaubersalt.  The  artificial  sulphate  of  baryta  is  found 
in  a  condition  of  extreme  fineness  and  purity,  possess- 
ing a  fine  lustre,  and  susceptible  for  producing  a  fine 
white  paint,  which  is  the  best  substitute  for  white  lead 
and  zinc  white,  is  not  subject  to  tarnish  or  become 
brown  in  parlors,  like  white  lead,  which  is  attacked  by 
hydrosulphuric  acid,  and  forms,  when  combined"  with 
the  liquid  glass,  a  slow  but  intimate  combination,  and 
is  likewise  used  under  the  name  of  blancfix  for  card- 
makers,  paper-stainers,  and  paper  collar  manufac- 
turers to  a  very  large  extent.  It  may  also  be  considered 
in  point  of  importance,  if  compared  with  that  of  white 
lead,  not  having  a  dilatory  effect  upon  health  as  the 
latter.  If  mixed  with  the  soluble  glass,  it  obviates  the 
odious  smell  of  linseed  oil  and  spirits  of  turpentine. 
If  it  is  mixed  with  dexterine,  starch,  or  other  binding 
material  in  connection  with  the  liquid  silicate  of  soda, 
its  applications  may  be  multiplied  to  any  extent. 

The  artificial  sulphate  of  baryta  is  largely  manufac- 
tured on  the  continent  of  Europe ;  in  the  United 
States  it  has  so  far  been  manufactured  in  New- York 
by  a  few  chemical  establishments  for  card-makers,  But 
not  yet  for  the  purpose  of  substituting  it  to  white  lead. 


62 


SILICIFICATION  OF  WOOD. 


SILICIFICATION  OF  WOOD. 

Wood,  and  all  other  organic  combustible  substances, 
may,  to  a  great  extent,  be  preserved  against  that  great 
element,  the  fire,  by  the  proper  application  of  the 
liquid  silicates.  Still  it  requires  much  skill,  experience 
and  proper  management  to  subdue  this  wonderful 
element  when  brought  to  its  full  power.  There  are 
many  instances  on  record  to  prove  either  a  full,  or  at 
least  partial  success  in  arresting  the  progress  of  a 
conflagration  by  the  impregnation  or  coating  of  com- 
bustible bodies  with  many  substances,  such  as  possess 
incombustibility,  whether  liquids,  gases,  or  materials 
which  possess  the  properties  of  generating  gases,  that 
will  withdraw  or  suffocate  the  surrounding  atmosphere, 
such  as  the  oxygen  gas,  and  thereby  arrest  the  progress 
of  the  flames.  Many  chemical  agents  have  been  from 
time  to  time  proposed  to  effect  this  object ;  such  as 
salt,  chloride  of  lime,  and,  latterly,  carbonic  acid  in  its 
gaseous  and  liquid  form,  and  many  metallic  salts  have 
proved  but  a  partial  success  in  the  prevention  of  decay 
or  dry  rot  of  wood.  The  soluble  glass  is  one  of  the 
first  materials  which  have  been  successfully  employed 
in  arresting  conflagration,  and  as  far  as  1823  this 
material  was  recommended  in  the  construction  of  the 
Munich  Theatre,  where  465,000  square  feet  of  timber 
surface  were  treated  witli  a  coating  of  the  liquid 
soluble  glass,  and  in  1830-31  and  '32  the  author  per- 
formed many  experiments  in  the  Brooklyn  Navy  Yard, 
partially  as  a  protecting  agent  against  fire,  as  also 
against  decay  of  the  woody  fibre.  Small  square  blocks 
of  wood,  after  having  been  impregnated  with  the  solu- 


SILICIFICATION  OF  WOOD. 


63 


ble  glass,  and  sailcloth,  writing  paper,  parchment,  etc., 
were  exposed  iof  some  time  to  the  flame  of  a  gas  lamp. 
After  the  lapse  of  an  hour,  all  these  substances  were 
found  to  be  charred,  but  not  consumed.  It  is  proved 
that  the  liquid  soluble  glass  produces  a  perfect  adher- 
ing, permanent  covering,  which,  when  properly  laid 
on,  suffers  no  damage  from  the  atmosphere.  For 
coating  the  wood,  etc.,  a  pure  solution  of  the  liquid 
glass  is  required,  otherwise  it  will  peel  ofl,  and  it  is 
best  not  to  use  it  first  in  a  concentrated  state,  as  it 
will  not  be  able  to  penetrate  into  the  pores,  whereby 
the  atmosphere  must  be  expelled,  and  even  five  or  six 
applications  may  be  made  in  intervals  of  twenty-four 
hours.  Although  this  process  renders  good  services, 
it  may  be  improved  by  the  addition  of  other  pulverized 
substances,  wherein  the  soluble  glass  acts  as  the  bind- 
ing material,  the  coating  assumes  a  better  body,  is 
stronger  and  more  permanent,  and  if  exposed  to  the 
fire,  a  crust  is  formed ;  such,  for  instance,  are  bone 
dust,  clay  and  chalk  mixed  together,  a  lead  glass,  etc. ; 
common  cla^^,  one-tenth  of  the  quantity  of  silicate  of 
soda,  was  successfully  used  with  the  liquid  glass  in  the 
Munich  Theatre.  If  applied  on  linen  or  other  organic 
textur3S,  the  mere  coating  or  dipping  is  not  sufficient,  , 
but  a  surface  between  rollers  must  be  resorted  to,  in 
order  to  produce  a  full  absorption  with  the  pores ; 
these  stuffs  may  then  be  rolled  up,  but  not  folded. 

Building  timber,  rail-road  sleepers,  and  other  similar 
materials,  have  been  treated  in  the  manner  just  de- 
scribed, and  were  protected  fully  against  fire  and  dry 
rot. 

The  author  proposed  a  combination  of  the  liquid 


64 


SILICIFICATION  OF  WOOD. 


glass  with  tlie  following  substances,  intended  as  de- 
composing agents  by  chemical  affinity,  and  producing 
in  the  cells  of  the  vegetable  fibre  the  various  mineral 
and  metallic  salts  which  are  altogether  insoluble  in 
water,  alkalies  and  acids,  and  he  extended  his  experi- 
ments on  the  uses  of  lime,  chalk,  gypsum,  .copperas, 
etc.  His  process  of  treating  ship  timber,  sleepers, 
cross-ties,  roofing  shingles,  and  other  wood  blocks, 
was  the  following : 

1.  The  materials  to  be  treated  were  put  in  steam 
boilers  and  exposed  for  four  hours  to  a  pressure  of  hot 
steam  (or  300^  F.),  then  withdrawn  from  the  kettles 
and  dried.  Alkalies  and  acids,  such  as  hydrochloric, 
have  been  since  recommended  for  the  purpose  of  ab- 
stracting color  and  albumen  existing  in  the  cells  of  the 
woody  fibres,  which,  however,  is  accomplished  by 
steaming. 

2.  In  a  solution  of  silicate  of  soda,  while  hot,  the 
materials  to  be  treated  are  thrown,  and  kept  there  for 
twenty-four  hours,  which  will  give  ample  time  for  the 
liquid  to  enter  into  the  open  cells  while  hot. 

d.  A  large  vat,  containing  either  lime  water,  solution 
of  copperas,  or  blue  vitriol,  white  vitriol  or  gypsum, 
finely  powdered  and  thrown  into  hot  water,  or  finely- 
powdered  chalk  of  1  pound  to  10  gallons  of  water  ;  the 
proportion  of  metallic  salts  is  but  one-quarter  jDound 
to  the  gallon  of  water.  The  woods  are  kept  in  the 
vats  for  another  day,  and  then  taken  out,  dried  and 
ready  for  use. 

Coal  tar,  and  the  other  products  of  dry  distillation 
from  tar  and  peat,  have  been  recommended  by  Krieg 
as  far  back  as  1858,  under  the  name  of  Creosote-car- 


SILICIFICATION  OF  WOOD. 


65 


bolic  acid,  which  was  then  considered  a  waste  product 
and  in  its  raw  state  having  a  specific  gravity  of  1.02 
to  1.058,  and  yielded  from  20  to  30  per  cent,  of  the 
tar  ;  it  was  well  known  to  possess  the  property  of  pro- 
protecting  wood  against  decay. 

This  chemist  combined  with  the  impregnation  of 
wood,  etc.,  the  soluble  glass  and  the  creosote-car- 
botic  acid,  for  the  reason  that  the  latter  precipitates 
the  soluble  silica  as  an  insoluble  substance  while  it  is 
soluble  in  an  alkaline  lye.  He  proposed  to  expose 
the  woods  for  three-quarters  of  an  hour  to  a  tempera- 
ture of  SOO'^  F.,  and  then  drying  them  thoroughly. 

The  woods  thus  prepared  showed  an  increased 
weight  of  6  per  cent.,  and  a  lacquered  surface,  while 
in  the  inside  the  pores  were  filled  with  an  insoluble 
precipitated  silica. 

For  effecting  a  still  more  perfect  success  is  to  fix 
the  creosote  on  the  woody  fibre  from  the  alkaline  so- 
lution, by  diluted  sulphuric  acid,  or  by  a  solution  of 
copperas,  (sulphate  of  iron,)  whereby  the  sulphate 
of  soda  thus  obtained  may  either  be  washed  out,  or 
oozed  out,  the  creosote-carbolic  acid  combines 
stronger  with  the  woody  fibre,  and  the  impregnated 
woods  may  be  considered  safely  protected  against  fire 
or  rot. 

This  process  just  described,  deserves  the  serious  at- 
tention of  the  various  companies  established  for  the 
last  five  years  in  the  preservation  of  wood  by  carbolic 
acid,  tar,  etc.,  by  combining  the  soluble  glass  with 
their  process,  as  we  have  described. 

Since  the  introduction  of  railroads,  not  quite  fifty 
years,  many  men  have  been  engaged  in  chemical  ex- 


66 


SILICIFICATION  OF  WOOD. 


periments  upon  the  cross-ties  and  sleepers,  which, 
after  being  laid  down  for  a  few  years,  undergo  the  de- 
cay or  rot,  and  have  to  be  renewed,  which  causes 
great  expense  to  the  companies.  Kyan,  Burnett, 
Laboucherieand  many  other  chemists  in  all  countries 
where  this  evil  existed,  proposed  remedies  ;  the  sub- 
limate, chloride  of  zinc,  p3Tolignite  of  iron,  all  had 
their  advantages  ;  of  late,  borax,  alum,  rosin,  carbolic 
acid  have  been  introduced. 

Wooden  Eoof  Shingles. 

One  of  the  most  valuable  applications  of  the  soluble 
glass  may  be  recommended  for  .shingles  and  wooden 
roofs  of  farm-houses  in  the  country  and  near  rail- 
roads, where  the  sparks  of  the  locomotives  have  fre- 
quently caused  conflagrations  and  destruction  of  pro- 
perty. 

The  operation  is  quite  simple,  and  the  expense  but- 
trifling  ;  the  process  has  already  been  described,  but 
it  may  be  still  more  simplified  in  the  following 
manner  : 

After  the  steaming  of  the  shingles  in  boilers  or  in 
tanks,  where  steam  of  250  to  350^  is  led  into  them, 
they  are  dried  and  thrown  into  a  weak  solution  of 
liquid  silica,  standing  about  25^  B.,  in  which  they  are 
left  for  twenty-four  hours,  when  they  are  taken  out 
and  exposed  to  the  air.  Before  they  are  quite  dry,  a 
weak  solution  of  chloride  of  calcium  is  thrown  over 
them  or  sprinkled  over  them  with  a  broom.  When 
quite  dry  they  are  fit  for  use.  They  will  not  burn 
nor  be  ignited  with  the  sparks  ;  if  exposed  to  a  direct 


SILICIFICATION  OF  WOOD. 


67 


fire,  will  not  light  in  a  surrounding  fire.  An  intense 
heat  of  long  duration  may  char  them  on  the  surface ; 
they  are,  however,  quite  safe  from  any  inflammation. 

Decay  of  Wood  and  Pbocesses  for  Preserving  it. 

According  to  the  experiments  which  were  made  by 
De  Saussure,  in  the  beginning  of  this  century,  it 
would  seem  that  the  decay  of  woody  fibre  was  exclu- 
sively caused  by  the  action  of  air  and  water.  On  ex- 
posing moist  wood  to  the  action  of  oxygen  gas,  he 
found  that,  for  every  volume  of  oxygen  absorbed  by 
the  wood,  one  volume  of  carbonic  acid  was  disengaged. 
It  is  now  conceded  that  it  is  the  hydrogen  of  the  fibre 
which  is  oxj^dized  at  the  expense  of  the  oxygen  of  the 
atmosphere,  while  the  carbolic  acid  is  solely  formed 
from  the  elements  of  the  wood,  or  that  the  process  is 
simply  a  separation  of  a  portion  of  the  carbon  of  the 
wood  by  direct  oxydation  ;  and  it  would  seem,  from 
the  experiment  mentioned,  that  the  first  and  only 
cause  of  the  deca^^  of  vegetable  tissue  must  be  ascribed 
to  the  affinity  of  oxygen  for  the  elements  of  the  latter. 

Such  cases  of  slow,  decomposition  have  indeed  also 
been  distinguished  by  the  name  eremacausis,  a  term 
composed  of  two  Greek  words,  and  meaning  to  burn 
by  degrees. 

The  above  explanation,  however,  scarcely  holds 
good  in  all  cases  ;  it  is  now  known  that,  in  dry  air, 
woody  fibre  may  be  preserved  without  decaying  for 
thousands  of  years  ;  and,  under  water,  in  certain  con- 
ditions, it  appears  to  be  equally  durable.  One  must, 
therefore,  look  for  some  other  cause  to  explain  the 
transformation  of  woody  fibre.    Such  a  one  presents 


68 


BILICIFICATION  OF  WOOD. 


itself  in  the  fact  that,  when  wood  is  exposed  for  some 
weeks  to  running  water,  or  if  it  is  boiled  in  water  and 
afterwards  dried  until  the  original  weight  is  restored, 
it  is  rendered  thereby  considerably  more  durable. 

The  cause  of  the  transformation  in  question  must, 
therefore,  be  sought  in  a  substance  which  is  removed 
by  the  dissolving  action  of  water  in  the  experiment 
mentioned.  By  further  investigation,  this  substance 
is  found  to  consist  of  the  albumen  of  the  sap,  which , 
is  distributed  throughout  the  cellular  tissue.  Like 
the  animal  albumen,  as  the  white  of  eggs,  which  it 
closely  resembles  both  in  properties  and  composition, 
the  vegetable  albumen  is  exceedingly  liable  to  decom- 
position. In  this  state  it  acts  like  a  ferment,  induc- 
ing the  decay  of  other  bodies,  according  to  the 
physical  law  propounded  in  another  application  by 
Laplace  and  Berthollet,  namely,  that  a  molecule  set 
in  motion  by  any  power  can  impart  its  own  motion  to 
another  molecule  with  which  it  may  come  in  contact. 

Among  the  bodies  most  prone  to  decomposition  is 
the  sugary  element,  which  is  first  dissolved.  Then 
the  growth  of  fungi  generally  begins,  and  the  putre- 
faction proceeds  step  by  step.  It  may,  therefore,  be 
considered  that  the  spontaneous  decomposition  of  the 
vegetable  albumen  is  the  primary  cause  of  the  decay 
of  wood.  It  is,  indeed,  found  that  those  kinds  of 
wood  which  contain  the  smallest  quantity  of  albu- 
minous matter  and  amylum  are  the  most  durable. 
Especially  is  this  the  case  with  a  certain  tree  of  the 
acacia  tribe,  the  locust  and  the  cedar,  which  resist 
decomposition  in  situations  where  all  other  kinds  of 
wood  soon  decay. 


SILICIFICATION  OF  WOOD. 


69 


In  order,  tlien,  to  find  out  whether  a  certain  kind 
of  wood  is  especially  fitted  for  building  purposes,  the 
quantity  of  albumen  present  in  the  fibre  should  be 
ascertained  by  analysis.  M.  Payen  recommends,  for 
this  pui7)ose,  to  digest  the  wood  in  a  dilute  solution 
of  caustic  alkali — this  soda,  or  potash — which  has  no 
action  on  the  woody  fibre,  but  only  dissolves  the  albu- 
men. Hence  the  quantity  of  the  latter  may  be  esti* 
mated  by  washing,  drying  and  weighing  the  wood 
after  the  experiment  has  been  made. 

The  capability  of  wood  to  sustain  the  strain  to 
which  it  must  necessarily  be  exposed,  especially  when 
moying  over  it  at  high  velocities,  has  been  satisfacto- 
rily proved  by  the  experience  of  the  Great  Western 
and  other  railwajs,  where  continuous  longitudinal 
sleepers  of  wood  have  been  employed,  and  experience 
has  shown  that  the  solidity  of  the  road  is  much 
greater  than  when  the  iron  rails  were  attached  either 
to  stone  blocks  or  transverse  wooden  sleepers.  In 
proof  that  wooden  rails  cut  from  beech  will  bear  the 
wear  and  tear  of  trains  passing  over  it,  it  is  well 
known  that  be^ch  logs  have  proven  to  last  eighteen 
to  twenty  years  when  working  in  gear  with  an  iron 
wheel.  The  rails  on  the  Yauxhall  line  were  prepared 
by  Payne's  patented  process  for  preventing  dry  rot 
and  decay  of  timber.  Scotch  fir,  if  subjected  to  pres- 
sure, will  crush  at  ten  tons,  while  beech  (the  wood  re- 
commended for  railways)  will  bear  a  pressure  of 
eighty-two  tons  before  it  begins  to  yield. 

Experience  ha-^ing  confirmed  the"  capability  of 
Scotch  fir  to  withstand  the  traffic  of  twelve  engines 
per  day  for  seven  hours,  without  any  visible  wear,  it 


70 


SILICIFICATION  OF  WOOD. 


would  be  difficult  to  say  how  long  the  rails  cut  from 
beech,  sustaining  eighty-two  tons  pressure,  would  last. 
Some  of  the  impediments  with  which  railroads  have 
to  contend  are  the  undulations  of  the  country,  and 
the  necessity  of  diverging  from  a  right  line  in  order 
to  obtain  the  traffic  of  important  towns.  These  ob- 
stacles can  only  be  overcome  by  an  outlay  of  capital, 
in  making  the  required  excavations  and  embankments, 
or  by  the  oftentimes  ruinous  system  of  tunneling ; 
and  after  all,  inclines  of  greater  or  less  radients  are 
unavoidable,  and  prevent  the  line  working  economi- 
cally. Curves  on  iron  rail-roads  are  highly  prejudi- 
cial, especially  if  the  radius  be  small,  as  the  wear  and 
tear  become  proportionately  increased. 

Timber  Eot  and  Seasoning. 

It  is  generally  supposed  that  the  rotting  of  timber 
is  merely  induced  by  the  action  of  the  oxygen  of  the 
aii\  From  analysis  made  of  sound  and  decayed  oak, 
it  has  been  shown  that  for  every  two  equivalents  of 
hydrogen  oxydized  by  the  air,  one  equivalent  of  car- 
bonic acid  had  separated.  It  may  therefore  be  in- 
ferred that  the  decay  or  rot  of  timber  does  not  arise 
from  fermentation,  but  is  rather  a  chemical  process. 
Others  admit  that  microscopical  parasites  of  vegeta- 
ble nature  play  an  important  part  in  the  decay  of 
wood  ;  but  consider  the  presence  of  albuminous  mat- 
ter in  the  sap  as  necessary,  which,  according  to  them, 
must  also  be  first  in  a  state  of  decomposition  before 
it  allows  the  growth  of  those  organisms.  In  order  to 
throw  light  upon  this  most  important  subject,  we  pro- 


SlLCCmCATION  OF  WOOD. 


71 


pose  first  to  tabulate  a  number  of  well  obseryed  facts. 
Sound  timber,  when  immersed  in.%water,  without  ac- 
cess of  air.  will  withstand  decay  for  almost  an 
unlimited  time.  This  is  proved  by  the  piles  upon 
which  the  dwelHngs  on  the  Canaries  rest,  which  were 
erected  in  the  time  of  the  Conquest  in  1402,  they 
being  just  as  sound  now  as  if  they  had  been  freshly 
felled.  Eoots  of  trees  that  have  been  submerged  in 
marshes  are  rarely  found  decomposed.  This  is  stated 
to  be  the  case  with  the  utensils  discovered  in  the  lake 
dwellings  of  Switzerland,  Bavaria  and  Lombardy, 
which  must  be  at  least  ten  thousand  years  old.  Har- 
tig  also  describes  a  cypress  stem  with  over  three 
thousand  rings,  representing  the  same  number  of 
years,  which,  though  submerged,  had  only  partially 
turned  into  brown  coal. 

The  German  botanist,  Schacht,  in  all  instances  of 
decayed  timber,  has  met  with  fungi  and  lichens.  The 
destruction  of  timber  by  decay,  after  the  same  has 
been  hewn,  must,  therefore,  be  considered  as  being 
produced  by  similar  causes  which  brought  on  the  dis- 
ease of  the  vine,  potato,  mulberry  trees,  and  other  cul- 
tivated plants,  which  make  the  years  1845,  '48,  '53,  '57 
and  others  forever  painful  to  the  memory. 

That  the  juice  should  be  in  a  state  of  decomposition 
before  being  capable  of  generating  those  organisms 
seems  doubtful,  since  this  has  not  been  found  the  case 
in  other  and  well  studied  modes  of  fermentation.  The 
morel,  a  species  of  mushroom,  will  also  attack  per- 
fectly sound  wood.  Hand  in  hand  with  the  spread  of 
the  fungi  continues  the  decomposition  of  the  ligneous 
tissue.    Access  to  moisture  and  air,  as  also  a  certain 


72 


SILICIFICATION  OF  WOOD. 


degree  of  heat,  are  necessary.  In  regard  to  the  air 
fungi  require  oxygen  for  their  generation.  When  aii^- 
dried,  steamed,  or  chemically  treated  and  afterward 
dried,  wood  commences  to  rot,  it  is  a  sign  that  moist- 
ure has  again  penetrated  ;  for  it  is  scarcely  to  be  ad- 
mitted, that  in  all  these  cases  the  sap  had  been  entirely 
removed.  Timber  decomposes  the  easier  the  more 
sap  it  contains  ;  and  if  green  trees  are  hewn  when  the 
vessels  are  overflowing  with  juice,  one  may  look  with 
certainty  for  diminished  durability  of  the  timber. 
Timber  is  not  always  the  more  durable  the  more  dense 
it  is,  but  rather  when  the  even  fineness  of  the  grain 
continues  to  the  pith  of  the  stem. 

The  Koman  historian,  Pliny,  considers  the  resin- 
ifer  ous  woods  as  the  most  durable.  Indeed,  nature 
shows  that  this  is  frequently  the  case.  The  resinifer- 
ous  red  and  white  pines  of  Oregon  and  California  are 
considered  first-class  ship  timber,  so  much  so  that  en- 
tire vessels  have  been  constructed  from  the  denser 
qualities.  The  yellow  or  long-leaved  pine,  in  dry  sit- 
uations, is  extremely  durable,  and  is  preferred  to  oak 
of  any  kind,  where  a  lighter,  yet  solid  wood,  is  re- 
quired. The  white  or  northern  pine,  which  grows 
abundantly  in  every  northern  State  of  the  Union,  from 
Maine  to  Minnesota,  reaching  often  to  an  altitude  of 
one  hundred  and  eighty  feet,  with  a  diameter  of  six 
feet  or  more,  is  said  to  retain  its  properties  as  long  as 
the  very  best  description  of  oak. 

The  proportion  in  which  the  w^oody  fibre  and  water 
are  to  each  other  is  very  different.  It  varies  accord- 
ing to  the  degree  of  dryness  and  the  nature  of  the 


SIUCIFICATION  OF  WOOD. 


73 


wood  itself.  According  to  Scliubler  and  NeuiBfer,  we 
Lave  for"  newlj-felled  woods  the  following  table  : 

"WOOD.  WATER. 

Hornbeam  ,  1 8 . 6  per  cent. 

Willow  26.0 

Sycamore  27.0 

Ash  28.7 

Birch  30.8 

Oak  34.7 

Pedich  Oak  35  4 

White  Fir  37.1 

Pine  39.7 

Ked  Beech  39.7 

Alder   .41.6 

Asp  43  7 

Elm  44.5 

•    Red  Fir  45  .2 

Lime  Tree  s  47.1 

Italian  Poplar  ,  48.2 

Larch  48.6 

White  Poplar  50.6 

Black  Poplar  51.8 

The  amount  of  water  in  wood,  after  one  year's  dry- 
ing in  the  air,  ranges  from  20  to  25  per  cent.,  and  when 
perfectly  air-dry,  as  it  is  called,  it  still  holds  from  10 
to  15  per  eent. 

The  specific  weight  of  newly-felled  timber  ranges 
from  0.85  to  1.05 ;  that  of  air-dried  timber  from  0.45 
to  0.75.  The  weight  of  one  cubic  foot  of  newly-cut 
native  timber  would  thus  range  from  50  to  65  pounds, 
while  that  of  seasoned  wood  would  vary  from  28  to  47 
pounds.  The  total  expulsion  of  moisture  by  means  of 
air-drying,  according  to  the  experiments  of  Rumford, 
takes  place  only  at  280^  Fahrenheit.  But  even  if  thus 
completely  dried,  and  then  exposed  again  to  the 
atmosphere,  it  absorbs  nearly  five  per  cent,  of  water 
during  the  first  three  days,  and  continues  to  absorb 
until  it  contains  from  fourteen  to  sixteen  per  cent., 


74 


SILICIFICATION  OF  WOOD. 


after  which  it  becomes  very  hygroscopic,  losing  or  ab- 
sorbing water  according  to  the  state  of  the  atmosphere. 

The  drying  of  lumber  in  confined  rooms  by  means 
of  hot  air,  or  steam  and  air  alternately,  is  now  largely 
practiced,  and  the  more  on  account  of  the  economy  of 
the  method  than  on  account  of  its  yielding  a  superior 
product.  In  some  cases,  the  wood,  before  being  ex- 
posed to  artificial  heat,  is  subjected  to  a  longitudinal 
pressure,  in  order  to  rupture  the  cells  in  which  the 
moisture^  is  confined,  to  the  end  that  it  may  escape 
more  freely  upon  the  application  of  heat.  It  is  claimed 
that  the  wood  is  thus  rendered  more  valuable  for  nearly 
all  the  purposes  for  which  it  is  used,  but  particularly 
for  the  hubs,  spokes,  and  panels  of  carriages,  etc. 

Wooden  Eoof  Shingles. 

One  of  the  most  valuable  applications  of  the  soluble 
glass  may  be  recommended  for  shingles  and  wooden 
roofs  of  farm-houses  in  the  country,  and  near  rail- 
roads, where  the  sparks  of  the  locomotives  have 
frequently  caused  conflagrations  and  destruction  of 
property. 

The  operation  is  quite  simple,  and  the  expense  but 
trifling.  The  process  has  already  been  described,  but 
it  may  be  still  more  simplified  in  the  following  manner : 

After  the  steaming  of  the  shingles  in  boilers  or  in 
tanks,  where  steam  of  300  to  350^  is  led  into  them  for 
several  honrs,  they  are  dried  and  thrown  into  a  weak 
solution  of  liquid  silica,  standing  about  25^  B.,  from 
which  they  are  taken  out  and  exposed  to  the  air  before 
they  are  quite  dry  ;  a  weak  solution  of  chloride  of  cal- 
cium is  thrown  over  them  or  sprinkled  over  them  with 


SILICIFICATION  OF  WOOD. 


75 


a  broom  ;  when  quite  dry,  they  are  fit  for  use.  They 
will  not  burn  nor  be  lighted  by  the  sparks  if  exposed 
to  a  direct  fire — will  not  light  in  a  surrounding  fire. 
An  intense  heat  of  long  duration  may  char  them  on 
the  surface ;  they  are,  however,  quite  safe  against  any 
inflammation. 

Street  Pavements. 

As  a  rule,  competent  engineers  express  doubts  as  to 
the  merits  of  the  Nicolson,  and  of  wooden  pavements 
of  all  patterns. 

In  the  Nicolson  structure,  the  road-bed  is  of  sharp, 
clean  sand,  of  the  proper  thickness.  A  basis  is  then 
made  by  laying  common  boards,  dipped  in  hot  coal- 
tar,  lengthwise  on  stringers  of  like  material,  laid  from 
curb  to  curb.  The  blocks  forming  the  superstructure 
are  of  Southern  hard  pine,  three  by  four,  and  are  set 
on  end  in  rows,  crosswise  of  the  street — the  blocks, 
before  setting,  being  dipped  to  half  their  length  in  a 
bath  of  coal-tar.  Between  the  rows  of  blocks  inter- 
vene pickets  of  thin  board  set  on  edge,  and  leaving  an 
opening  between  the  rows  of  blocks  of  an  inch  or 
nearly  in  depth.  This  opening  is  filled  with  clean 
screened  gravel,  rammed  down  with  a  paver's  ham- 
mer, and  an  iron  blade  made  for  the  purpose,  and  the 
surface  is  covered  with  hot  coal-tar.  The  gutter  exhibits 
its  lowest  point  half  a  foot  from  the  curb.  The  whole 
surface  is  covered  with  coal-tar  sufficiently  boiled  to 
be  tough  and  fibrous,  but  not  brittle,  upon  which  is 
sprinkled  a  layer  of  fine  gravel  and  common  sand. 
The  Staffard  pavement  differs  from  the  Nicolson,  in 
the  laying  of  large  blocks  prepared  after  the  Seely 


78 


SILICIFICATION  OF  WOOD. 


patent,  resting  upon  stringers,  which  in  their  turn  may 
be  supported  by  any  specified  road-bed.  Provided 
the  road-bed  is  sufficiently  secure,  say  of  strong  con- 
crete, and  the  upper  deposit  is  made  sufficiently  com- 
plete, the  Stafford  Pavement  cannot  but  compare 
favorably  with  other  wooden  pavements,  and,  for  sim- 
plicity, is  quite  superior  to  the  Nicolson. 

Various  Systems  Adopted  for  Eoadway  Pavements. 

A  great  variety  of  systems  have  been  adopted  for 
roadway  pavements.  The  most  convenient  classifica- 
tion of  ^them  is  into  gravel  compositions,  broken 
stone,  plank,  wooden  block,  cobble  stone  or  pebble 
stone  block  and  iron  block  pavements  and  tramways. 
The  first  attempts  at  pavements  generally  commence 
with  the  use  of  gravel.  Roads  thus  made  possess  the 
advantages  of  cheapness  of  material  and  construction. 
In  the  Central  Park,  where  there  are  probably  the 
most  perfect  roads  in  this  country,  they  have  shown 
better  endurance  than  those  made  on  the  MacAdam 
plan.  Gravel  roads,  when  properly  constructed  and 
maintained,  are  comparatively  smooth  and  noiseless, 
besides  afi"ording  excellent  foothold  for  horses.  The 
great  objections  to  them  are  that  they  cannot  be  kept 
firm  enough  to  afford  easy  draught  for  heavy  traffic  ; 
that  they  lack,  in  a  high  degree,  permanence,  and  are 
constantly  requiring  repairs  ;  that  they  are  difficult  to 
keep  clean  and  to  drain  properly  ;  the  rapidly  grind- 
ing and  crushing  to  powder  tending  greatly  to  cause 
dust  in  dry  weather  and  mud  in  wet  weather  ;  and, 
lastly,  that  the  best  construction  yet  attained  has 
failed  to  prevent  them  from  washing  into  gullies. 


SILICIFICATION  OF  WOOD. 


77 


Under  the  head  pf  second  composition  pavements, 
may  properly  be  included  pavements  formed  by  the 
combinations  of  several  materials,  such  as  the  famous 
asphalte  pavement  of  Paris,  concrete,  beton,  gutta 
percha,  slag,  cinder,  and  other  pavements  ;  also  those 
formed  according  to  the  experiments  of  M'Neil,  partly 
of  broken  stone  and  partly  of  pieces  of  cast  metal,  laid 
on  a  sub-pavement  of  rubble  stone.  The  asphalte 
pavement  of  Paris,  so  often  recommended  in  news- 
paper articles,  is  really  quite  an  imperfect  pavement. 
It  is  generally  formed  on  a  foundation  of  Mac- 
Adamized  road.  Powdered  asphalte  is  placed  on  the 
foundation,  and  stamped  with  hot  rammers  until  it  is 
very  hard,  and  has  a  thickness  of  one  or  two  inches. 
It  is  very  pleasant  and  smooth  to  ride  over,  but  re- 
requires  most  constant  watching  and  repairing.  It  is 
slippery  in  wet  weather,  and  excessively  so  at  a  freez- 
ing temperature. 

The  Fiske  Conorete  Pavement. 

'  This  pavement  is  composed  of  seventy  per  cent,  in 
bulk  of  broken  stone,  coal  or  gravel,  clean  coal  or 
iron  cinders,  not  over  three  inches  in  any  dimensions. 
These  are  passed  over  a  screen  with  meshes  one  quar- 
ter inch  square.  The  coarser  portion  is  then  coated 
by  mixing  with  tar,  warm  or  cold,  and  then  spread 
on  the  road-bed  and  heavily  rolled  until  a  depth  of 
four  inches  is  attained.  The  finer  portion  is  then 
mixed  with  clean  sharp  sand,  warmed,  and  then 
thoroughly  mixed  with  tar,  to  which  has  been  added 
rosin,  carbojapanis  or  pitch.  This  is  placed  on  the 
first  layer  of  coarse  material,  and  rolled  until  a  depth 


78 


SILICIPICATION  OF  WOOD. 


of  two  inches  is  attained ;  after  which  the  surface  is 
covered  with  an  excess  of  clean  sharp  sand,  and  again 
rolled. 

The  Nicolson  Pavement. 

We  now  come  to  the  subject  of  wooden  pavements. 
The  first  general  attempt  to  use  wooden  blocks  for 
pavements  took  place  some  thirty  years  ago,  both  in 
this  country  and  Europe.  They  are  generally  made 
in  the  form  of  hexagonal  prisms  of  hard  wood,  laid 
directly  on  sand  or  earth.  Leading  off  in  the  list  of 
wooden  pavements  adopted  in  this  city  is  the  Nicol- 
son pavement.  In  laying  this  pavement,  the  street  is 
first  prepared  by  a  sufficient  covering  of  sand,  which 
is  brought  to  the  proper  crown  with  a  straight  edge 
made  for  that  purpose.  This  surface  is  then  covered 
with  common  round  inch  boards,  laid  lengthwise  with 
the  line  of  the  street.  The  ends  of  these  boards  rest 
on  stringers  of  the  same  material  laid  from  curb  to 
curb. 

Both  sides  of  these  boards  are  covered  with  hot 
coal-tar.  The  blocks  are  of  Southern  pine,  three 
inches  "wide  and  six  inches  deep,  and  are  set  on  end 
in  rows  cro*sswise  of  the  street.  Before  setting,  the 
blocks  are  dipped  to  half  their  height  in  hot  coal-tar. 
Between  each  row  of  blocks,  and  at  their  base,  pickets 
one  inch  thick  and  three  inches  wide  are  nailed  on 
edge.  The  opening  thus  formed  between  the  rows  is 
filled  with  clean  screened  gravel,  rammed  with  a 
paver's  rammer,  an  iron  blade  made  for  that  purpose 
and  then  colored  with  hot  coal-tar.  The  whole  of 
the  upper  surface  of  the  pavement,  when  laid,  is 


SILrCIFICATION  OF  WOOD. 


79 


covered  with  hot  coal  tar,  boiled  to  a  consistency 
which,  when  cold,  is  to  be  tough,  fibrous  and  not 
brittle,  and  then  covered  with  fine  gravel  and  common 
sand.  After  the  top.  gravel  has  become  packed  on 
the  surface  and  in  the  grooves,  the  street  is  swept. 

The  Staffoed  Pavement 

is  only  another  imitation  of  the  great  original  Nicol- 
son.  The  blocks  are  dressed  to  a  uniform  thickness, 
grooved  in  the  middle  with  a  double  dovetail,  two 
and  one-half  by  three-fourth  inches,  each  side  of  the 
block  beveled  at  one  end,  and  running  to  an  edge  so 
as  to  form  a  groove  on  the  upper  surface. 

General  Directions  for  The  Protection  of  Eail- 
EoAD  Sleepers,  Cross  Ties,  Frame  Houses,  Tele- 
graph Poles,  Timber,  Staves,  Shingles,  Laths, 
Tanks,  Tubs,  Casks,  Barrels,  (Petroleum,  Naptha, 
Spirits  Turpentine  Alcohol,  Linseed  Oil,)  Cisterns 
AND  Every  Description  of  Wood,  against  Fire,  Dry 
EoT  AND  Leakage. 

The  seasoning  or  initiatory  preparation  of  the  lum- 
ber, so  as  to  destroy  the  organic  or  nitrogenized  mat- 
ters enclosed  in  all  the  cells  of  vegetable  matters,  are 
dissolved  and  washed  out  of  it ;  or,  in  other  words, 
the  removal  of  all  the  albumen,  sap  and  coloring  mat- 
ter, is  effected  by  exposing  from  four  to  six  hours  to 
boiling  water,  containing  about  one  per  cent,  of  soda 
ash  in  solution.  They  are  then  withdrawn  and  dried 
in  hot  rooms,  and  then  thrown  into  tanks  containing 
the  tar  and  carbolic  acid  water,  and  left  for  a  few 
hours,  then  dried  again  and  thrown  into  a  hot  solution 
of  silicate  of  soda,  standing  20  ^  B.,  in  which  they  are 


80 


SILICIFICATION  OF  WOOD. 


left  for  ten  or  twelve  Lours.  When  removed  from 
here  a  weak  hmewash  is  apphed  with  a  brush  or 
sponge,  consisting  of  10  lbs.  slaked  lime  to  40  gallons 
of  water,  when  likewise  thej  are  removed  to  a  dry  or 
hot  air  ;  after  that  a  weak  wash  of  chloride  of  calcium 
is  thrown  or  brushed  over  them  when  nearly  dry. 
The  process  is  then  finished,  and  the  articles  so  pre- 
pared will  resist  the  elements  as  above  stated.  They 
increase  in  weight  by  this  process  aboat  6  per  cent. 
After  this  treatment,  they  assume  upon  the 'first  dry- 
ing a  glazed  appearance,  and  the  pores  are  filled  with 
insoluble  silicas  precipitated  by  the  action  of  the  tar 
liquor  upon  the  alkali  of  the  silicate  of  soda.  Barrels 
which  have  been  treated  may  be  rendered  perfectly 
impervious,  by  filliug  up  the  chimes  (the  inside  of 
those  barrels  having  been  treated  with  the  silicate  of 
soda  and  chloride  of  calcium)  with  a  thin  silicated 
cement  applied  on  the  interstices.  No  air  nor  any 
liquid  will  then  have  any  effect ;  the  ligliest  liquid 
may  then  be  kept  in  those  prepared  barrels  without 
escapihg  ;  flour,  butter,  lard,  and  many  other  perisha- 
ble substances  may  be  kept  for  a  length  of  time  in 
barrels  so  prepared.  Spirits  of  turpentime,  linseed 
oil,  alcohol,  and  other  spirituous  liquors,  may  safely 
be  transported  and  kept  for  a  length  of  time,  -without 
evaporation  or  loss  in  the  contents  of  the  barrels. 
Telegraph  poles,  which  are  from  twenty  to  thirty  feet 
long,  require  a  different  treatment  for  their  seasoning 
before  they  undergo  the  silicification.  They  are 
steeped  first  in  the  tar  carbolic  liquid,  in  holes  dug  in 
the  ground  with  tanks  built  in  the  same,  and  left  ia 
there  for  several  days  ;  then  taken  out,  and  under- 


CEMENTS. 


81 


going  the  otlier  process  of  silicate  of  soda,  lime  wash 
and  chloride  of  calcium,  as  described,  will  render  them 
proof  against  fire  and  dry  rot. 


CEMENTS. 
TiiE  Most  Adhesive  Lubricator. 

Black  lead,  6  lbs.,  are  mixed  with  3  lbs.  slaked 
lime ;  8  lbs.  sulphate  of  baryta  are  mixed  with  7  lbs. 
of  linseed  oil ;  the  whole  mass  is  well  mixed  together 
to  a  uniform  consistency,  and  the  entire  mass  made 
more  plastic  with  concentrated  solution  of  silicate  of 
soda.  This  cement  may  be  used  for  numerous  pur- 
poses, where  hardness  and  adhesiveness  are  the  de- 
sired objects,  uniting  at  the  same  time  steam  and 
hot  water.  For  locomotives,  engines  and  machinery 
it  is  prepared  from  a  mixture  of  silicate  of  soda 
liquid,  at  25^  B.,  added  to  a  fine  plumbago,  talc 
asbestos  in  equal  quantities,  so  as  to  retain  the  thin 
plastic  condition,  and  capable  of  dropping  it  on  the 
journals  in  very  small  portions. 

The  CHEAPEST  WHITEWASH,  which  is  very  durable  for 
indoor  and  outdoor  work,  is  pi-epared  by  the  follow- 
ing composition  :  To  1  lb.  slaked  lime  and  1  lb.  sul- 
phate baryta,  add  1  pint  of  silicate  of  soda  and  1 
pailful  of  hot  water ;  stir  the  materials  well  to,Gjether, 
and  use  it  at  once.  If  the  color  is  intended  for  a 
yellow  wash,  add  a  quarter  of  a  lb.  chrome  yellow  ; 
if  for  a  blue  wash,  use  instead  of  the  latter  a  quarter 
of  a  lb.  ultramarine,  (worth  six  cents;)  and  if  the 


82 


CEMENTS. 


paint  is  intended  to  coat  iron  railing,  stoves,  steam- 
boat chimneys,  and  to  obtain  a  brown  or  black  fire- 
proof paint,  add  half  a  lb.  of  manganite,  an  oxide  of 
manganese,  or  the  pyrolusite,  which  is  the  black  or 
gray  peroxide  of  manganese. 

The  white-wash  or  yellow-wash  just  quoted  is  ex- 
tremely durable  and  cheap  for  wooden  fences  along 
railroad  tracks,  canal  boats,  farm  houses  and  other 
wooden  structures. 

The  Most  Durable  Aquarium  Cement. 

Tlie  materials  of  a  water-resisting  composition  are 
prepared  by  mixing  finely  powdered  dry  silicate  of 
soda,  powdered  chalk,  and  fine  sand  in  equal  quan- 
tities, made  plastic  mth  the  liquid  silicate,  and  applied 
at  the  joints,  and  worked  over  with  fluid  chloride  of 
calcium,  and  when  quite  dry  let  some  weak  hydroflu- 
oric acid  pass  over  the  cemented  joints.  This  cement 
will  be  permanently  impervious  to  water,  and  will  not 
crack.  The  same  composition  is  quite  suitable  for 
breweries,  malt  houses,  linings  for  water  tanks,  and 
cellars  into  which  water  flows. 

The  author  considers  it  advisable  to  show,  also,  the 
advantages  of  concrete,  by  quoting  Tail's  system,  ap- 
plied in  Paris,  and  the  description  of  the  concrete 
bridge  at  London,  and  will  state,  that  the  addition  of 
silicate  of  soda  to  the  concrete  wdll  undoubtedly  en- 
sure a  great  saving. 

The  material  consists  of  one  part  of  Portland  ce- 
ment to  eight  parts  of  coarse  gravel.  The  cement 
and  gravel  are  first  well  mixed  together  in  a  dry  state, 


CEMENTS. 


83 


and  when  this  is  done  it  is  damped  by  means  of  a 
large  watering  pot,  containing  some  hot  silicate  of 
soda,  and  again  mixed  by  a  pronged  drag,  such  as  is 
used  for  dragging  dung  out  of  a  cart,  until  the  entire 
heap  has  been  wetted  and  mixed  together.  It  is  then 
put  in  iron  or  zinc  pails  and  poured  into  the  frame, 
where  it  is  levelled  by  men  stationed  for  the  purpose. 
In  order  to  save  concrete,  large  lumps  of  stones  or 
brickbats  are  put  into  the  centre  of  the  wall,  and  cov- 
ered over  and  about  with  concrete.  Frost  does  not 
affect  the  concrete  after  it  has  once  set,  which,  with 
good  cement,  will  be  in  about  live  or  six  hours.  Nor 
do  heavy  rains  appear  to  injure  it  .in  the  slightest  de- 
gree, though  they  may  chance  to  fall  ere  the  concrete 
has  hardened.  The  walls  can  be  made  straight  and 
even  as  it  is  possible  for  walls  to  be,  and  the  corners 
as  sharp  and  neat  as  if  they  had  been  formed  of  the 
most  carefully  dressed  stone. 

The  Soluble  Glass  as  Manure  foe  Grapevines. 

By  putting  the  dry  silicate  of  soda  at  the  roots  of 
grapevines,  with  or  without  the  addition  of  phosphate 
of  lime,  has,  by  experiments,  proved  of  immense 
benefit  to  the  thriving  of  the  vines  to  a  proper  thick- 
ness, and  the  grapes  of  uncommon  size. 

The  Soluble  Glass  a  Substitute  for  Glue. 

It  has  proved  quite  useful  in  applying  the  liquid 
glass  for  glueing  wood  and  paper  together,  instead  of 
the  common  glue,  and  it  is  sold  in  the  trade  as  mu- 
cilage, and  applied  on  pasteboard  instead  of  emery 


84 


CEMENTB. 


or  corundum  paper,  and  used  by  cabinet-makers  and 
other  mechanics  for  polishing.  As  a  paste  for  book- 
binders instead  of  giue,  starch  or  dexterine,  it  has 
proved  quite  useful.  Earthenware  may  be  kept  more 
durable  by  lining  them  with  a  weak  solution.  It  is 
likewise  used  on  leather,  provided  the  same  is  not  ex- 
posed to  much  bending. 

The  glazing  or  enamelwg  of  culinary  vessels,  made 
either  for  iron  or  stone  ware,  the  soluble  glass  is  use- 
fully applied  in  the  following  manner  : 

The  silicate  solution  of  soda  and  potash  is  mixed 
with  thick  lime  water  ;  to  100  parts  of  the  silicate  add 
1  part  of  lime  water,  made  from  1  part  caustic  lime 
to  6  parts  of  water.  The  mixture  is  then  evaporated 
to  dryness  and  reduced  to  fine  powder.  By  dipping 
first  the  objects  to  be  glazed  in  the  liquid  silica,  the 
powder  is  then  sifted  over  them  ;  when  dry,  the 
operation  is  repeated  again  ;  when  dry,  the  coating 
becomes  so  hard  that  it  cannot  be  rubbed  off  by  the 
hands ;  they  are  then  treated  hke  other  ware  by 
putting  them  in  a  furnace,  requiring,  however,  not  a 
very  great  heat. 

A  similar  process  is  to  prepare  a  mass  from  100 
parts  powdered  quartz,  80  parts  pure  potash,  10  parts 
saltpetre,  and  20  parts  slaked  lime,  which  mixture 
is  made  into  a  thin  paste  with  the  liquid  silicate,  and 
then  burnt.  Tha  glazing  is  very  durable,  and  resists 
both  vegetable  and  mineral  acids  like  common  glass. 
It  requires  no  great  skill  to  execute  the  operation, 
and  the  expense  to  prepare  such  a  glazing  is  but  a 
trifle. 


CEMENTS. 


85 


Soluble  Glass  Application  roPt  Various  Cements. 

Forcelain,  Glass  and  Bletals  are  fastened  together 
when  broken,  either  by  the  hquid  or  gelatinous  siH- 
cate  by  the  following  method  :  Heat  the  object  to  be 
fastened  together  to  that  of  boiling  water,  and  apply 
the  soluble  glass  on  both  sides  of  the  fracture,  press 
them  together  and  leave  them  in  a  warm  place  for  a 
fortnight,  when  they  will  be  fit  for  use.  Flourspar 
finely  ground,  black  oxide  of  manganese,  oxide  of  iron 
(crocus)  finely  powdered  soluble  glass,  and  many 
more  refractory  substances  are  suitable  articles  to  mix 
with  the  liquid  silica  for  the  various  cements  in  use. 
.  A  cement  for  fastening  iron  in  stone,  glass  or  wood  is 
recommended,  consisting  in  1  part  prepared  chalk,  1 
part  marble  dust,  and  made  plastic  with  the  liquid 
silica,  or  1  part  powdered  soluble  glass,  2  parts  pow- 
dered flourspar,  made  into  a  paste  with  the  liquid 
silica,  and  this  is  for  pasting  labels  on  glass  bottles. 

Fireproof  Cement  is  composed  of  the  various  oxides 
of  iron,  and  formed  into  a  paste  with  the  liquid 
silica. 

The  Ilarhle  Cement  is  composed  of  carbonate  of 
lime,  carbonate  of  magnesia  and  silica  with  oxide  of 
iron,  and  made  into  a  thin  liquid  and  applied  to  the 
stone,  which,  on  drying,  is  permanently  fastened  to 
the  surface,  and  protects  it  from  smoke,  dust  and 
atmospheric  agents. 

Common  and  fire  brick  acquire  great  strength  if  the 
silicate  of  soda  has  been  employed  in  the  manufacture, 
and  become  indestructible  ;  they  are  then  particularly 


86 


CEMENTS. 


fifc  for  baker's  ovens,  wall  and  well  foundations  and 
furnace  beds. 

Glazed  Paper  for  apothecaries'  use,  may  likewise 
be  prepared  with  the  soluble  glass. 

Metallic  Cement  is  formed  of  a  mixture  of  equal 
parts  of  oxide  of  zinc,  peroxide  of  manganese  and 
litharge,  and  made  up  with  liquid  silica  and  marble 
dust,  and  applied  between  the  metals  to  be  cemented. 

An  Impermeable  Cement  Kesisting  Steam. 

It  is  prepared  by  mixing  six  parts  finely  powdered 
black  lead,  3  parts  slaked  lime,  and  8  parts  of  Plaster 
of  Paris,  made  into  consistency  by  the  liquid  silica. 

Zinc  Cement,  for  stopping  cracks  in  metallic  appa- 
ratus and  other  materials,  is  made  by  mixing  equal 
weights  of  zinc  white  and  finely  powdered  soluble 
glass  with  a  solution  of  chloride  of  zinc  of  the  den- 
sity of  126  ;  it  sets  rapidly  and  resists  th^  action  of 
most  agents.  The  simple  mixture  of  oxide  of  zinc 
with  a  solution  of  the  chloride  of  zinc,  has  also  been 
recommended. 

Hard  Cement. 

It  consists  in  mixing  5  parts  powdered  clay,  2  parts 
iron  fihng,  and  1  part  of  black  oxide  of  manganese, 
and  J  part  borax,  made  into  paste  with  liquid  sihca ; 
when  dry  is  very  hard,  and  withstands  water.  Also, 
a  mixture  oi  manganese  and  zinc  luhite  with  Plaster  of 
Paris  forms  a  very  hard  cement,  and  has  great  ad- 
hesive capacity. 

Brain  and  gas  pipes,  for  conducting  to  sewers  and 
houses,  may  be  made  as  permanent  as  iron  pipes  by 


CEMENTS. 


87 


using  a  hard  cement,  consisting  of  hydraulic  hme, 
clay  and  sand,  mixed  with  fine  powdered  fluorspar  and 
soluble  glass,  all  made  plastic  by  the  liquid  silica  ; 
this  mass,  when  dry  and  burnt,  will  resist  a  pressure 
of  600  pounds  to  the  square  inch,  while  iron  pipes, 
burst  under  a  pressure  of  400  pounds  to  the  square 
inch. 

Cement  for  CLOsiNa  Cracks  in  Stoves. 

It  is  prepared  by  mixing  finely  pulverized  iron,  such 
as  can  be  procured  at  the  druggists,  with  liquid 
water  glass,  to  a  thick  paste,  and  then  coating  the 
cracks  with  it.  The  hotter  the  fire,  the  more  does 
the  cement  melt  with  its  metallic  ingredients,  and 
the  more  completely  will  the  crack  become  closed. 

Cement  for  a  Cistern. 

Ta'ke  10  parts  of  Plaster  of  Paris, 
2         "    Glauber  Salts. 
•  4        "  Clay. 
4        "    Slaked  Lime. 

Made  in  a  plastic  cement  with  the  liquid  silicate  of 
soda,  and,  before  it  hardens,  add  liquid  chloride  of 
calcium. 

For  sweetening  the  water  in  cisterns,  which  is  found 
to  be  hard,  may  be  made  soft  by  one  gallon  of  silicate 
of  soda  in  the  cistern,  and  repeat  the  operation  once  a 
month. 

Tlie  best  iron  cement  is  composed  of  calcined  plaster 
and  iron  filings,  from  each  10  parts,  4  parts  oxide 
manganese,  2  parts  slaked  lime;  made  plastic  with  the 
liquid  siHcate  of  soda. 


88 


CEMENTS. 


A  Sthong  Cement  for  Iron. 

To  4-5  parts  claj,  dry  and.  powdered,  2  parts  iron 
filings,  1  part  manganese,  J  part  salt.  J-  part  borax,  in 
a  paste  made  with  soluble  glass,  or  equal  parts  zinc 
white  and  manganese,  made  to  a  paste,  must  be  used 
immediately. 

Iron  Cement  for  Water  and  Gas  Pipes  and  Castings. 

It  is  obtained  from  60  parts  cast  iron  turnings, 
mixed  with  2  parts  of  sal  ammonia,  1  part  fluor  sulphur, 
and  1  part  lime  cement ;  the  whole  made  plastic  by  the 
liquid  glass  just  before  using  it,  to  mend  holes  of  what- 
ever description  in  iron  pipes  or  iron  castings  ;  it  be- 
comes soon  very  hard,  and  every  crevice  is  filled. 

Colored  Cements. 

To  a  solution  of  silicate  of  soda»of  1.298,  add,  while 
stirring,  first  pulverized  and  previously  washed  lixivia- 
ted chalk,  so  as  to  form  a  thick  mass,  to  which  are 
added,  for  coloring  purposes,  the  following  substances : 

For  black,  sulphuret  of  antimony. 

Gray,  iron  filings. 

Gray  white,  zinc  dust. 

Bright  green,  carbonate  of  copper. 

Blue,  orange  and  red,  cobalt,  vermilion  and  carmine. 

This  cement  hardens  in  six  to  eight  hours,  and  bears 
polishing  like  marble. 

Coating  for  Outside  Walls. 

The  following  coating  for  rough  brick  walls  is  used 
by  the  United  States  Government  for  painting  light- 
houses, and  it  effectually  prevents  moisture  from  strik- 


CEMENTS. 


89 


ing  tlirougli :  Take  of  fresli  Eosendale  cement  tliree 
parts,  and  of  clean,  fine  sand  one  part ;  mix  with  soluble 
glass  thoroughly.  This  gives  a  gray  or  granite  color, 
dark  or  light,  according  to  the  color  of  the  cement. 
If  brick  color  is  desired,  add  enough  Venetian  red  to 
the  mixture  to  produce  the  c6lor.  If  a  very  light  color 
'is  desired,  lime  may  be  used  with  the  cement  and  sand. 
Care  must  be  taken  to  have  all  the  ingredients  well 
mixed  together.  In  applying  the  wash,  the  wall  must 
be  wet  with  clean  fresh  water ;  then  follow  immediately 
with  the  cement  wash.  This  prevents  the  bricks  from 
absorbing  the  water  from  the  wash  too  rapidly,  and 
gives  time  for  the  cement  to  set.  The  wash  must  be 
well  stirred  during  the  application.  The  mixture  is  to 
be  made  as  thick  as  can  be  applied  conveniently  with 
a  whitewash  brush.  It  is  admirably  suited  for  brick- 
work, fences,  etc.,  but  it  cannot  be  used  to  advantage 
over  paint  or  whitewash. 

PHESEKYATION  OF  StoNES  FROM  GrEEN  CoATING. 

The  decay  of  granite,  marble,  limestones,  sandstones, 
and  all  natural  building  stones,  is  the  combined  effect 
of  various  causes,  and  among  these  is  a  very  minute 
lichen,  the  Lepra  antiquitalis,  which  is  one  of  the 
worst  enemies  of  stone,  and  its  action  is  to  such 
an  extent  that,  for  instance,  the  beautiful  maj-ble 
sculptures  of  the  well-known  Pare  de  Versailles 
will,  unless  proper  measures  be  taken  for  siaj^- 
ing  the  process  of  decay,  be  unsightly  and  ugly 
masses  of  dirt,  and  quite  irretrievably  lost,  as  works 
of  art,  within  the  next  50  years.  Various  places  and 
instances  are  cited  of  the  application  of  oxide  of 


90 


CEMENTS. 


copper  and  its  salts,  whicli  places  are  open  to  inspec- 
tion ;  and  the  length  of  time  which  has  elapsed  since 
such  application,  seems  to  warrant  the  conclusion 
that  these  compounds  act  as  preservatives  of  stone. 
In  reference  to  granite,  the  author  states  that  this 
stone  is  also,  according  to  the  experience  of  Egj^ptian 
engineers,  far  more  readily  affected  by  a  moist  climate 
than  one  would  be  led  to  believe.  The  obelisk  of 
Luxur,  brought  from  Upper  Egypt  to  Paris,  has  be- 
come blanched  and  full  of  small  cracks  during  the 
40  years  it  has  stood  on  the  Place  de  la  Concorde  ; 
although  40  centuries  had  not  perceptibly  affected  it 
as  long  as  it  was  in  Egypt.  Granite  in  a  moist 
climate  becomes  the  seat  of  a  minute  cryptogamic 
plant,  which  greatly  aids  its  destruction  ;  and  it  is, 
moreover,  a  well-known  fact,  that  the  disintegration 
of  this  stone,  which  is  composed  of  three  separate 
minerals,  (quartz,  mica,  and  felspar),  depends  very 
greatly  upon  the  thorough  and  intimate  mixture,  as 
well  as  the  chemical  composition,  of  thesa  three  in- 
gredients, each  of  which,  in  a  separate  state,  more 
easily  withstands  the  influence  of  the  weather. 

The  most  refractory  cement  is  formed  from  silica^ 
asbestos^  plumbago  and  soapstone.  These  materials, 
mixed  in  certain  proportions  and  made  plastic  by 
the  liquid  silica,  form  a  most  valuable  cement  for 
locomotive  journals  and  other  lubricating  purposes, 
for  lining  of  steam  boilers  as  well  as  coating,  for 
filling  up  airholes  in  iron  castinge.  By  the  addition 
of  peroxide  of  manganese,  it  may  be  much  improved, 
and  serve  as  a  permanent  paint,  which  is  fire  and 
water  proof. 


SPECIAL  NOTICE 


To  Bail  lioad  Companies,  Superintendents,  and  blaster 
Mechaivica. 


Rail  Road  Sleepers,  Cross  Ties, 

SHINGLE  EOOFS, 
STATION  HOUSES,  BBIDGES,  dc, 

PROTECTED  AGAINST 

The  Sparks  of  Locomotives,  Direct  Fire,  and 
Dry  Rot. 

THE  MANUFACTUEEKS  OF  THE  IMPRO\'ED 
SOLUBLE  GLASS  OR  SILICATE  OF  SODA, 

Beg  to  call  the  attention  of  those  interested  in  the 
construction  of  railroads  that  they  are  prepared  to 
furnish  all  quantities  of  the  liquid,  either  for  impreg- 
nating or  covering  materials  used  in  the  construction 
of  railroads,  with  full  directions  for  the  entire  suc- 
cess of  painting  the  sheds,  fences,  and  outposts  on 
the  line  of  railroads,  thereby  preventing,  very  fre- 
quently conflagrations  and  the  loss  of  valuable  pro- 
perty. 

For  hardening  mortars,  cements,  artificial  stone, 
common  brick  so  as  to  resist  a  greater  degree  of  heat 
and  exposure  to  dampness. 

The  soluble  glass  is  invaluable,  and  proved  be- 
yond contradiction,  that  if  wood  is  saturated  with  it 
by  a  very  simple  process,  say  shingles,  clapboards, 
sleepers,  or  ties  on  the  canvas  as  a  covering  of  rail- 
road cars,  a  double  advantage  is  achieved  ;  the  pro- 
tection against  fire  and  the  security  against  decay  ; 


92 


SPECIAL  NOTICE. 


it  may  cliar  or  smotliei,  if  exposed  to  a  great  confla- 
gration, but  it  will  never  burst  into  flames,  no  scatter- 
ing of  cinders,  or  blowing  about  of  firebrand.  The 
application  is  quite  simple,  and  the  price  extremely 
reasonable. 

Directions  for  use  : — In  a  tank,  containing  about 
120  gallons  boiling  water,  put  a  barrel  of  soluble 
glass,  containing  about  40  gallons  ;  the  various  rail- 
road materials  to  be  treated  are  thrown  in  and  kept 
for  two  or  three  hours  ;  they  are  taken  out  and  ex- 
posed for  an  hour  to  the  air,  and  then  are  painted 
with  a  whitewash  brush  of  the  whiting,  2  lbs.  to  1 
gallon  water,  or  a  paint  of  white  zinc  may  be  applied 
when  the  wood  is  perfectly  dry. 

For  further  particulars  and  contracts  apply  to  the 
original  manufacturers, 

L.  &  J.  W.  FEUCHTWANGEE, 

Manufacturing  Chemists  and  Drug  Importers, 

55  CEDAR  STBEET,  NEW  YOIIK. 


Special  Notice  to  Soap,  Trunk,  Pasteboard,  Band- 
box and  other  Manufacturers  of  Paper  or  Paints  and 
Paper  Hangings.  The  improved  soluble  glass  is  par- 
ticularly recommended  to  the  above  trades,  as  being 
superior  to  glue,  starch  or  flour  paste  ;  it  does  not 
crust,  and  is  very  economical. 


8^ -^5:15  ^3 


